Touch sensor system, and electronic device

ABSTRACT

A touch sensor system includes a driver which drives on the basis of code sequences which are orthogonal to one another and include +1 or −1 and each of which has a length N. A decoding section estimates on the basis of a first inner product operation of the outputs and the code sequences a first capacitance value and on the basis of a second inner product operation of the outputs and the code sequences a second capacitance value. A touch panel has a two-dimensional region including a hand placing region and a remainder region and processing sections.

TECHNICAL FIELD

The present invention relates to a touch sensor system configured todetect a touch signal that is based on a touch to a touch panel, whichtouch sensor system operates in accordance with a method for estimatingor detecting a coefficient, a device value, or a capacitance in a linearsystem configured in a matrix, and an electronic device.

BACKGROUND ART

There has been known a device for detecting linear device valuesdistributed in a matrix. Patent Literature 1, for example, discloses atouch sensor device (contact detecting device) for detectingdistribution of capacitance values of a capacitance matrix Cij (i=1, . .. , M and j=1, . . . , L) formed between M drive lines and L senselines. The touch sensor device operates in accordance with a scanningdetection method; specifically, the touch sensor device sequentiallyselects one of the drive lines and thus detects respective values oflinear devices connected to the drive line selected.

Patent Literature 2 discloses a capacitance detecting circuit which (i)in driving a plurality of drive lines, switches between a first driveline group and a second drive line group on the basis of a time seriescode sequence, (ii) outputs a measured voltage obtained by converting,into an electric signal, a sum total of respective currents acrosscapacitances, connected to sense lines, at a plurality of intersectionsof driven drive lines with the sense lines, and (iii) performs aproduct-sum operation of such a measured voltage and the code sequencefor each sense line so as to find a voltage value corresponding to acapacitance at each intersection.

As shown in Patent Literature 6, a conventional touch sensor systemconfigured to detect how capacitance values are distributed attempts tocarry out recognition of a finger and part of a hand which are incontact with a touch panel, by means of signal processing. For example,assume that a hand holding a stylus is in contact with a touch panel. Asignal based on how the touch panel is touched significantly changesover time according to action of moving the stylus etc.

(a) to (d) of FIG. 20 are views for describing touch signals observedwhen a hand is placed on a touch panel. As shown in (a) of FIG. 20, aregion where the hand is placed on the touch panel is small at first,i.e., the region is a region 116 a. Then, as shown in (b) of FIG. 20,the region where the hand is placed on the touch panel expands over timeto a region 116 b. Next, as shown in (c) of FIG. 20, the region wherethe hand is placed on the touch panel further expands over time, and atip of a stylus held in the hand makes contact with the touch panel.This causes a stylus input region 118 to appear. After that, as shown in(d) of FIG. 20, the region where the hand is in contact with the touchpanel changes from the region 116 c to a region 116 d, and a region 117where a finger is in contact with the touch panel appears.

CITATION LIST

Patent Literature 1

Japanese Patent Application Publication, Tokukai, No. 2010-92275 A(Publication Date: Apr. 22, 2010)

Patent Literature 2

Japanese Patent Publication No. 4364609, specification (PublicationDate: Jun. 16, 2005)

Patent Literature 3

Japanese Patent Publication No. 4387773, specification (PublicationDate: Jun. 16, 2005)

Patent Literature 4

Japanese Patent Application Publication, Tokukai, No. 2005-114362 A(Publication Date: Apr. 28, 2005)

Patent Literature 5

Japanese Patent Application Publication, Tokukai, No. 2005-134240 A(Publication Date: May 26, 2005)

Patent Literature 6

U.S. Pat. No. 7,812,828, specification (Oct. 12, 2010)

SUMMARY OF INVENTION Technical Problem

The touch sensor device of Patent Literature 1 operating in accordancewith the scanning detection method is, however, disadvantageous in thatthe touch sensor device is required to complete within a period of time(T/m) a process of simultaneously selecting and scanning a plurality oflines so as to detect capacitances of the capacitance matrix Cij. Forthe above symbol T/m, T represents a period of time given to obtaintwo-dimensionally distributed capacitance values, and m represents anumber of scans.

Accuracy of a detecting process generally improves by a process such asaveraging, as a process time is longer. On the other hand, (i) theperiod of time T given to obtain capacitance values needs to be shorterin order for the touch sensor device to follow a high-speed operation,and (ii) the number m of scans needs to be larger for improvement ofresolution. Either of (i) and (ii) problematically reduces the processtime (T/m) and thus decreases detection accuracy.

The capacitance detecting circuit of Patent Literature 2, to cancel anoffset error in a measured voltage, (i) switches between driving thefirst drive line group and driving the second drive line group on thebasis of a code sequence and (ii) subtracts a measured voltage based onthe driving of the second drive line group from a measured voltage basedon the driving of the first drive line group (see the specification,paragraphs [0058] and [0061]). The capacitance detecting circuit,however, carries out a two-stage operation and is problematically lesseffective in simultaneously achieving a high-speed operation and powerconsumption reduction.

It is difficult to accurately distinguish among the signals from theregions that appear and change as shown in (a) to (d) of FIG. 20. Thatis, it is difficult to accurately distinguish among a signal based on aninput with a stylus, a signal generated in response to a hand beingplaced on a touch panel, and a signal generated in response to a fingermaking contact with the touch panel. This causes a problem in which asignal based on an input with a stylus, a signal generated in responseto a hand being placed on the touch panel and a signal generated inresponse to a finger making contact with the touch panel may berecognized falsely.

It is an object of the present invention to provide a touch sensorsystem and an electronic device, each of which (i) achieves both a highdetection accuracy and a high resolution and (ii) allows a high-speedoperation.

Another object of the present invention is to provide a touch sensorsystem that does not falsely recognize a signal based on an input with astylus.

Solution to Problem

In order to solve the above problem, a touch sensor system of thepresent invention includes a driving section that (a) drives, on a basisof code sequences di (=di1, di2, . . . , diN, where i=1, . . . , M)which are orthogonal to one another and include elements each beingeither +1 or −1 and each of which has a length N, M drive lines inparallel for each of (I) a first capacitance column C1i (i=1, . . . , M)formed between the M drive lines and a first sense line and (II) asecond capacitance column C2i (i=1, . . . , M) formed between the Mdrive lines and a second sense line, so that a voltage +V is applied foran element of +1 in the code sequences and that a voltage −V is appliedfor an element of −1 in the code sequences, and thus (b) outputs outputssFirst=(s11, s12, . . . , s1N) from the first capacitance column andoutputs sSecond=(s21, s22, . . . , s2N) from the second capacitancecolumn; an estimation section that estimates, (a) on a basis of a firstinner product operation of the outputs sFirst and the code sequences di,a first capacitance value in the first capacitance column which firstcapacitance value corresponds to a k1-th drive line and (b) on a basisof a second inner product operation of the outputs sSecond and the codesequences di, a second capacitance value in the second capacitancecolumn which second capacitance value corresponds to a k2-th drive line;a sensor panel corresponding to the drive lines, the sense lines, thefirst capacitance column, and the second capacitance column, the sensorpanel including a two-dimensional region including at least one partialregion and a remainder region being a region other than the partialregion; first processing means for carrying out a first process inaccordance with a partial region touch signal corresponding to a touchto the partial region; and second processing means for carrying out asecond process in accordance with a remainder region touch signalcorresponding to a touch to the remainder region, the second processbeing different in kind from the first process, said at least onepartial region being a hand placing region that includes a region wherea hand is placed for input to the sensor panel; the partial region touchsignal being a hand placing region touch signal corresponding to a touchto the hand placing region, and the remainder region touch signalincluding a plot signal generated by a stylus and/or a touch signalgenerated by a finger.

According to this feature, the first process is carried out inaccordance with the partial region touch signal corresponding to a touchto the partial region, and the second process that is different in kindfrom the first process is carried out in accordance with the remainderregion touch signal corresponding to a touch to the remainder region.This makes it possible to carry out processes in which (i) a signalbased on an unintended touch input with respect to the partial regionand (ii) a signal based on an intended touch input with respect to theremainder region are dealt with separately from each other. As a result,it is possible to provide a touch sensor system that does not falselyrecognize a signal based on an unintended touch input with respect tothe partial region as a signal based on an intended input with a styluswith respect to the remainder region.

Another touch sensor system of the present invention includes a sensorpanel including (I) a first capacitance column C1i (i=1, . . . , M)formed between M drive lines and a first sense line and (II) a secondcapacitance column C2i (i=1, . . . , M) formed between the M drive linesand a second sense line; and an integrated circuit for controlling thesensor panel, the integrated circuit including: a drive section for (a)driving, on a basis of code sequences di (=di1, di2, . . . , diN, wherei=1, . . . , M) which are orthogonal to one another and include elementseach being either +1 or −1 and each of which has a length N, the M drivelines in parallel for each of (I) the first capacitance column C1i (i=1,. . . , M) and (II) the second capacitance column C2i (i=1, . . . , M)so that a voltage +V is applied for an element of +1 in the codesequences and that a voltage −V is applied for an element of −1 in thecode sequences, and thus (b) outputting outputs sFirst=(s11, s12, . . ., s1N) from the first capacitance column and outputs sSecond=(s21, s22,. . . , s2N) from the second capacitance column; and an estimationsection for estimating (a) on a basis of a first inner product operationof the outputs sFirst and the code sequences di, a first capacitancevalue in the first capacitance column which first capacitance valuecorresponds to a k1-th drive line and (b) on a basis of a second innerproduct operation of the outputs sSecond and the code sequences di, asecond capacitance value in the second capacitance column which secondcapacitance value corresponds to a k2-th drive line, the sensor panelincluding a two-dimensional region including at least one partial regionand a remainder region being a region other than the partial region, theintegrated circuit further including: first processing means forcarrying out a first process in accordance with a partial region touchsignal corresponding to a touch to the partial region; and secondprocessing means for carrying out a second process in accordance with aremainder region touch signal corresponding to a touch to the remainderregion, the second process being different in kind from the firstprocess, said at least one partial region being a hand placing regionthat includes a region where a hand is placed for input to the sensorpanel, the partial region touch signal being a hand placing region touchsignal corresponding to the touch to the hand placing region, and theremainder region touch signal including a plot signal generated by astylus and/or a touch signal generated by a finger.

An electronic device of the present invention includes the touch sensorsystem; and a display panel which either is placed on the sensor panelincluded in the touch sensor system or contains the sensor panel.

A yet another touch sensor system of the present invention includes adriving section that (a) drives, on a basis of code sequences di (=di1,di2, . . . , diN, where i=1, . . . , M) which are orthogonal to oneanother and include elements each being either +1 or −1 and each ofwhich has a length N, M drive lines in parallel for each of (I) a firstcapacitance column Ci1 (i=1, . . . , M) formed between the M drive linesand a first sense line and (II) a second capacitance column Ci2 (i=1, .. . , M) formed between the M drive lines and a second sense line, andthus (b) outputting, to an analog integrator, outputs sFirst=(s11, s12,. . . , s1N) from the first capacitance column and outputs sSecond=(s21,s22, . . . , s2N) from the second capacitance column; and an estimationsection that estimates, (a) on a basis of a first inner productoperation of the outputs sFirst and the code sequences di, a firstcapacitance value in the first capacitance column which firstcapacitance value corresponds to a k1-th drive line and (b) on a basisof a second inner product operation of the outputs sSecond and the codesequences di, a second capacitance value in the second capacitancecolumn which second capacitance value corresponds to a k2-th drive line,the driving section, for an element of +1 in the code sequences, drivingthe drive lines at (i) a first voltage when the analog integrator isreset and (ii) a second voltage when the outputs sFirst and sSecond fromthe first and second capacitance columns are sampled and, for an elementof −1 in the code sequences, driving the drive lines at (i) the secondvoltage when the analog integrator is reset and (ii) the first voltagewhen the outputs sFirst and sSecond from the first and secondcapacitance columns are sampled, the touch sensor system furtherincluding: a sensor panel corresponding to the drive lines, the senselines, the first capacitance column and the second capacitance column,the sensor panel including a two-dimensional region including at leastone partial region and a remainder region being a region other than thepartial region; first processing means for carrying out a first processin accordance with a partial region touch signal corresponding to atouch to the partial region; and second processing means for carryingout a second process in accordance with a remainder region touch signalcorresponding to a touch to the remainder region, the second processbeing different in kind froth the first process, said at least onepartial region being a hand placing region that includes a region wherea hand is placed for input to the sensor panel, the partial region touchsignal being a hand placing region touch signal corresponding to a touchto the hand placing region, and the remainder region touch signalincluding a plot signal generated by a stylus and/or a touch signalgenerated by a finger.

A yet another touch sensor system of the present invention includes: adrive section that (a) drives, on a basis of code sequences di (=di1,di2, . . . , diN, where i=1, . . . , M) which are orthogonal to oneanother and include elements each being either +1 or −1 and each ofwhich has a length N, M drive lines in parallel for each of (I) a firstcapacitance column Ci1 (i=1, . . . , M) formed between the M drive linesand a first sense line and (II) a second capacitance column Ci2 (i=1, .. . , M) formed between the M drive lines and a second sense line, andthus (b) outputting, to an analog integrator, outputs sFirst=(s11, s12,. . . , s1N) from the first capacitance column and outputs sSecond=(s21,s22, . . . , s2N) from the second capacitance column; and an estimationsection that estimates (a) on a basis of a first inner product operationof the outputs sFirst and the code sequences di, a first capacitancevalue in the first capacitance column which first capacitance valuecorresponds to a k1-th drive line and (b) on a basis of a second innerproduct operation of the outputs sSecond and the code sequences di, asecond capacitance value in the second capacitance column which secondcapacitance value corresponds to a k2-th drive line, the drive section,before outputting to the analog integrator the outputs sFirst andsSecond from the first and second capacitance columns, (a) driving, whenthe analog integrator is reset and when the outputs sFirst and sSecondfrom the first and second capacitance columns are sampled, the drivelines at a first voltage so that the outputs sFirst and sSecond from thefirst and second capacitance columns are outputted to the analogintegrator, (b) reading out, from the analog integrator, the outputssFirst and sSecond from the first and second capacitance columns asfirst offset outputs and second offset outputs, respectively, and (c)storing the first and second offset outputs in a memory, the touchsensor system further including: a sensor panel corresponding to thedrive lines, the sense lines, the first capacitance column and thesecond capacitance column, the sensor panel including a two-dimensionalregion including at least one partial region and a remainder regionbeing a region other than the partial region; first processing means forcarrying out a first process in accordance with a partial region touchsignal corresponding to a touch to the partial region; and secondprocessing means for carrying out a second process in accordance with aremainder region touch signal corresponding to a touch to the remainderregion, the second process being different in kind from the firstprocess, said at least one partial region being a hand placing regionthat includes a region where a hand is placed for input to the sensorpanel, the partial region touch signal being a hand placing region touchsignal corresponding to a touch to the hand placing region, and theremainder region touch signal including a plot signal generated by astylus and/or a touch signal generated by a finger.

A yet another touch sensor system of the present invention includes: asensor panel including (I) a first capacitance column Ci1 (i=1, . . . ,M) formed between M drive lines and a first sense line and (II) a secondcapacitance column Ci2 (i=1, . . . , M) formed between the M drive linesand a second sense line; and an integrated circuit for controlling thesensor panel, the integrated circuit including: a drive section for (a)driving, on a basis of code sequences di (=di1, di2, . . . , diN, wherei=1, . . . , M) which are orthogonal to one another and include elementseach being either +1 or −1 and each of which has a length N, the M drivelines in parallel for each of (I) the first capacitance column Ci1 (i=1,. . . , M) and (II) the second capacitance column Ci2 (i=1, . . . , M),and thus (b) outputting, to an analog integrator, outputs sFirst=(s11,s12, . . . , s1N) from the first capacitance column and outputssSecond=(s21, s22, . . . , s2N) from the second capacitance column; andan estimation section for estimating (a) on a basis of a first innerproduct operation of the outputs sFirst and the code sequences di, afirst capacitance value in the first capacitance column which firstcapacitance value corresponds to a k1-th drive line and (b) on a basisof a second inner product operation of the outputs sSecond and the codesequences di, a second capacitance value in the second capacitancecolumn which second capacitance value corresponds to a k2-th drive line,the drive section, for an element of +1 in the code sequences, drivingthe drive lines at (i) a first voltage when the analog integrator isreset and (ii) a second voltage when the outputs sFirst and sSecond fromthe first and second capacitance columns are sampled and, for an elementof −1 in the code sequences, driving the drive lines at (i) the secondvoltage when the analog integrator is reset and (ii) the first voltagewhen the outputs sFirst and sSecond from the first and secondcapacitance columns are sampled, the sensor panel including atwo-dimensional region including at least one partial region and aremainder region being a region other than the partial region, theintegrated circuit further including: first processing means forcarrying out a first process in accordance with a partial region touchsignal corresponding to a touch to the partial region; and secondprocessing means for carrying out a second process in accordance with aremainder region touch signal corresponding to a touch to the remainderregion, the second process being different in kind from the firstprocess, said at least one partial region being a hand placing regionthat includes a region where a hand is placed for input to the sensorpanel, the partial region touch signal being a hand placing region touchsignal corresponding to the touch to the hand placing region, and theremainder region touch signal including a plot signal generated by astylus and/or a touch signal generated by a finger.

A yet another touch sensor system of the present invention includes: asensor panel including (I) a first capacitance column Ci1 (i=1, . . . ,M) formed between M drive lines and a first sense line and (II) a secondcapacitance column Ci2 (i=1, . . . , M) formed between the M drive linesand a second sense line; and an integrated circuit for controlling thesensor panel, the integrated circuit including: a drive section for (a)driving, on a basis of code sequences di (=di1, di2, . . . , diN, wherei=1, . . . , M) which are orthogonal to one another and include elementseach being either +1 or −1 and each of which has a length N, the M drivelines in parallel for each of (I) the first capacitance column Ci1 (i=1,. . . , M) and (II) the second capacitance column Ci2 (i=1, . . . , M),and thus (b) outputting, to an analog integrator, outputs sFirst=(s11,s12, . . . , s1N) from the first capacitance column and outputssSecond=(s21, s22, . . . , s2N) from the second capacitance column; andan estimation section for estimating (a) on a basis of a first innerproduct operation of the outputs sFirst and the code sequences di, afirst capacitance value in the first capacitance column which firstcapacitance value corresponds to a k1-th drive line and (b) on a basisof a second inner product operation of the outputs sSecond and the codesequences di, a second capacitance value in the second capacitancecolumn which second capacitance value corresponds to a k2-th drive line,the drive section, before outputting the outputs sFirst and sSecond fromthe first and second capacitance columns to the analog integrator, (a)driving, when the analog integrator is reset and when the outputs sFirstand sSecond from the first and second capacitance columns are sampled,the drive lines at a first voltage so that the outputs sFirst andsSecond from the first and second capacitance columns are outputted tothe analog integrator, (b) reading out, from the analog integrator, theoutputs sFirst and sSecond from the first and second capacitance columnsas first offset outputs and second offset outputs, respectively, and (c)storing the first and second offset outputs in a memory, the sensorpanel including a two-dimensional region including at least one partialregion and a remainder region being a region other than the partialregion, the integrated circuit further including: first processing meansfor carrying out a first process in accordance with a partial regiontouch signal corresponding to a touch to the partial region; and secondprocessing means for carrying out a second process in accordance with aremainder region touch signal corresponding to a touch to the remainderregion, the second process being different in kind from the firstprocess, said at least one partial region being a hand placing regionthat includes a region where a hand is placed for input to the sensorpanel, the partial region touch signal being a hand placing region touchsignal corresponding to the touch to the hand placing region, and theremainder region touch signal including a plot signal generated by astylus and/or a touch signal generated by a finger.

An electronic device of the present invention includes: the touch sensorsystem; and a display panel which either is placed on the sensor panelincluded in the touch sensor system or contains the sensor panel.

Advantageous Effects of Invention

With a touch sensor system in accordance with the present invention, afirst process is carried out in accordance with a partial region touchsignal corresponding to a touch to the partial region, and a secondprocess is carried out in accordance with a remainder region touchsignal corresponding to a touch to the remainder region, which secondprocess is different in kind from the first process. This makes itpossible to carry out processes in which (i) a signal based on anunintended touch input with respect to the partial region and (ii) asignal based on an intended touch input with respect to the remainderregion are dealt with separately from each other. As a result, it ispossible to provide a touch sensor system that does not falselyrecognize a signal based on an unintended touch input with respect tothe partial region as a signal based on an intended input with a styluswith respect to the remainder region.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a circuit diagram illustrating a configuration of a touchsensor system of a first embodiment.

FIG. 2 is a block diagram illustrating a configuration of an estimationsection of an integrated circuit included in the touch sensor system.

FIG. 3 is a diagram describing a method for driving a sensor panelincluded in the touch sensor system.

FIG. 4 is a timing chart describing the method for driving the sensorpanel.

FIG. 5 is a diagram illustrating a first specific example of orthogonalcode sequences as an input to the sensor panel included in the touchsensor system.

FIG. 6 is a diagram illustrating a second specific example of theorthogonal code sequences.

FIG. 7 is a diagram illustrating a third specific example of theorthogonal code sequences.

FIG. 8 is a timing chart illustrating a method for driving a sensorpanel included in a touch sensor system of Embodiment 2.

FIG. 9 is another timing chart illustrating the method for driving thesensor panel included in the touch sensor system of Embodiment 2.

FIG. 10 is a diagram illustrating a method for driving a sensor panel ofEmbodiment 3.

FIGS. 11 (a) and (b) are each a diagram illustrating a code sequence foruse in driving a sensor panel of Embodiment 4.

FIG. 12 is a diagram illustrating a code sequence for use in driving asensor panel of Embodiment 5.

FIG. 13 is a graph illustrating a method for driving the sensor panel.

FIG. 14 (a) is a diagram for explaining code sequences of the aboveEmbodiments which code sequences are based on an M-sequence, and (b) is,a diagram illustrating a specific example of the code sequences based onan M-sequence.

FIG. 15 is a functional block diagram illustrating a configuration of amobile telephone including the touch sensor system.

FIG. 16 is a view schematically showing a configuration of a touchsensor system in accordance with Embodiment 7.

FIG. 17 is a view showing a hand placing region that is set on a touchpanel of the touch sensor system.

FIGS. 18 (a) and (b) are views each showing an example of how the handplacing region is set by a user.

FIGS. 19 (a) and (b) are views each showing an example of how the handplacing region is set by a user.

FIG. 20 (a) to (d) are views for describing touch signals observed whena hand is placed on a touch panel.

DESCRIPTION OF EMBODIMENTS

Embodiments of a touch sensor system of the present invention aredescribed below with reference to FIGS. 1 through 19.

(Embodiment 1)

(Configuration of Touch Sensor System of Embodiment 1)

FIG. 1 is a circuit diagram illustrating a configuration of a touchsensor system 1 of the present embodiment. The touch sensor system 1includes: a sensor panel 2; and an integrated circuit 3 for controllingthe sensor panel 2. The sensor panel 2 includes: M drive lines DL1through DLM provided in a horizontal direction in parallel to oneanother so as to be separated from one another at a predeterminedinterval; L sense lines SL1 through SLL provided in such a direction asto cross the drive lines and in parallel to one another so as to beseparated from one another at a predetermined interval; and capacitancesCij (where i=1 to M, and j=1 to L) provided in a matrix of M rows×Lcolumns at respective intersections of the M drive lines DL1 through DLMwith the L sense lines SL1 through SLL.

The integrated circuit 3 includes: a drive section 4 connected to the Mdrive lines DL1 through DLM; and an estimation section 5. FIG. 2 is ablock diagram illustrating a configuration of the estimation section 5included in the integrated circuit 3.

The estimation section 5 includes: L analog integrators 6 connected tothe L sense lines SL1 through SLL, respectively; a switch 7 connected tothe L analog integrators 6; an AD converter 8 connected to the switch 7;an inner product computing section 9 connected to the AD converter 8;and a RAM 10 connected to the inner product computing section 9. Theanalog integrators 6 each include: an operational amplifier with a firstinput grounded; an integral capacitance Cint provided between an outputof the operational amplifier and a second input thereof; a firsttransistor connected to the second input of the operational amplifier;and a second transistor connected to the second input in parallel to thefirst transistor.

The integrated circuit 3 further includes an application processingsection 11 which is connected to the inner product computing section 9and which carries out a gesture recognition process (for example, ARM)at 240 Hz. The integrated circuit 3 thus includes both analog circuitsand digital circuits.

(Operation of Conventional Touch Sensor System)

The description below deals first with an operation of the conventionaltouch sensor device disclosed in Patent Literature 1 mentioned above,and then with an operation of the touch sensor system 1 of the presentembodiment in detail. The following looks at detection of capacitancesCij (where i=1, . . . , M, and j=1, . . . , L) formed in a matrix atrespective intersections of M drive lines and L sense lines, andspecifically at scanning detection in which the individual drive linesare sequentially selected.

Capacitances Cij (j=1, . . . , L) connected to a selected drive line areeach supplied with a voltage V so as to store an electric charge(signal) Cij×V. Supposing that this signal is read out via a sense lineso that a gain G is obtained, a signal to be detected is expressed asfollows:G×Cij×V  (Formula 1)

(Operation of Touch Sensor System of Present Embodiment)

FIG. 3 is a diagram illustrating a method for driving the sensor panel 2included in the touch sensor system 1. Constituents illustrated in FIG.3 which are identical to their respective equivalents illustrated andreferred to in FIGS. 1 and 2 are each assigned the same reference signaccordingly. Such constituents in FIG. 3 are not described in detailhere.

First, the present embodiment of the present invention prepares codesequences di (=di1, di2, . . . , diN, where i=1, . . . , M). The codesequences di are orthogonal to one another and include +1 and −1.Further, the code sequences di each have a code length N. Theorthogonality of the code sequences di (=di1, di2, . . . , diN, wherei=1, . . . , M) each with a code length N means that the code sequencesdi satisfy the following condition:

$\begin{matrix}{{{di} \cdot {dk}} = {\sum\limits_{j = 1}^{N}{{dij} \times {dkj}}}} \\{= {N \times \delta\;{ik}}}\end{matrix}$

-   -   where    -   δik=1 if i=k    -   δik=0 if i≠k

The drive section 4 drives the M drive lines DL1 through DLM in parallelon the basis of the code sequences di so that a voltage +V is applied toeach capacitance corresponding to +1 and a voltage −V is applied to eachcapacitance corresponding to −1. The capacitances Cij (where i=1 to M,and j=1 to L) consequently each store an electric charge (signal) ±Cij·Vin accordance with a corresponding element (+1 or −1) in the codesequences.

The analog integrators 6 then each (i) add, via its connection to acorresponding sense line, electric charges stored in capacitancesconnected to the sense line and thus (ii) read out a signal for itscorresponding sense line. The analog integrators 6 consequently obtainoutput sequence vectors sj (=sj1, sj2, . . . , sjN, where j=1, . . . ,L).

FIG. 4 is a timing chart illustrating the method for driving the sensorpanel 2. First, a reset signal resets (i) the integral capacitances Cintof the respective analog integrators 6 and (ii) the capacitancesprovided in the sensor panel 2 in a matrix. The term “reset” as usedherein means to discharge a capacitance. Next, the drive lines DL1through DLM are driven in parallel each at Vref+V or Vref−V inaccordance with each value (+1 or −1) of d11, d21, d31, . . . , dM1 in acode sequence. This causes each corresponding capacitance to store anelectric charge ±CV in accordance with a corresponding element ±1 of thecode sequence. Then, a corresponding one of the analog integrators 6 (i)adds, via its connection to a corresponding sense line, electric chargesstored in the capacitances connected to the sense line and thus (ii)reads out a signal for its corresponding sense line. The analogintegrator 6 then outputs a result represented by

$G \times {\sum\limits_{k = 1}^{M}\left( {{Cki} \times V \times {dki}} \right)}$(in this circuit, G=−1/Cint), which is next subjected to an ADconversion in the AD converter 8 in accordance with a sampling signal.

The above operation produces output sequence vectors sji expressed as

${sji} = {G \times {\sum\limits_{k = 1}^{M}\left( {{Ckj} \times V \times {dki}} \right)}}$and therefore,

${sj} = {\sum\limits_{k = 1}^{M}\left( {{Ckj} \times V \times {dk}} \right)}$To find an inner product di·sj of a code sequence di and an outputsequence vector sj,

$\begin{matrix}\begin{matrix}{{{di} \cdot {sj}} = {{{di} \cdot G} \times {\sum\limits_{k = 1}^{M}\left( {{Ckj} \times V \times {dk}} \right)}}} \\{= {G \times {\sum\limits_{k = 1}^{M}\left( {{Ckj} \times V \times {{di} \cdot {dk}}} \right)}}} \\{= {G \times {\sum\limits_{k = 1}^{M}\left( {{Ckj} \times V \times N \times \delta\;{ik}} \right)}}} \\{= {G \times {Cij} \times V \times N}}\end{matrix} & \left( {{Formula}\mspace{14mu} 2} \right)\end{matrix}$

-   -   where    -   δik=1 if i=k    -   δik=0 if i≠k

Comparison between Formula 1 and Formula 2 shows that the method of thepresent embodiment makes it possible to detect a signal which is N timesas large as a signal detected by the conventional scanning readoutmethod.

The gain G is 1/Cint in a case where signals are read out via the senselines with use of the analog integrators 6 illustrated in FIGS. 1 and 2,that is, electric charge integrators each including an operationalamplifier provided with an integral capacitance Cint.

The drive section 4 of the integrated circuit 3 thus drives the M drivelines in parallel so that for each of a first capacitance column Cip(where p is not smaller than 1 and not larger than (L−1), and i=1, . . ., M) and a second capacitance column Ciq (where p<q, q is not smallerthan 2 and not greater than L, and i=1, . . . , M), voltages +V and −Vare applied to capacitances so as to correspond to +1 and −1 of a codesequence, respectively, in accordance with the code sequences di (=di1,di2, . . . , diN, where i=1, . . . , M) which are orthogonal to oneanother and include elements of +1 and −1 and each of which has a lengthN. The drive section 4 then causes (i) the first capacitance column tooutput sFirst (=sp1, sp2, . . . , spN) and (ii) the second capacitancecolumn to outputs sSecond (=sq1, sq2, . . . , sqN).

The outputs sFirst (=sp1, sp2, . . . , spN) from the first capacitancecolumn are each integrated by a corresponding analog integrator 6,whereas the outputs sSecond (=sq1, sq2, . . . , sqN) from the secondcapacitance column are also each integrated by a corresponding analogintegrator 6. The switch 7 sequentially selects one of the analogintegrators 6, respectively corresponding to the sense lines SL1 throughSLL, so as to supply to the AD converter 8 outputs from each capacitancecolumn which have each been integrated by a corresponding analogintegrator 6.

Specifically, the output sp1 is first read out from the firstcapacitance column to a first analog integrator 6 and integrated by thefirst analog integrator 6, while simultaneously, the output sq1 is readout from the second capacitance column to a second analog integrator 6and integrated by the second analog integrator 6. Then, the switch 7connects to the first analog integrator 6 so as to supply to the ADC 8the output sp1 read out and integrated as above. The switch 7 thendisconnects from the first analog integrator 6 and connects to thesecond analog integrator 6 so as to supply to the ADC 8 the output sq1read out and integrated as above. Next, the output sp2 is read out fromthe first capacitance column to the first analog integrator 6 andintegrated by the first analog integrator 6, while simultaneously, theoutput sq2 is read out from the second capacitance column to the secondanalog integrator 6 and integrated by the second analog integrator 6.Then, the switch 7 connects to the first analog integrator 6 so as tosupply to the ADC 8 the output sp2 read out and integrated as above. Theswitch 7 then disconnects from the first analog integrator 6 andconnects to the second analog integrator 6 so as to supply to the ADC 8the output sq2 read out and integrated as above. This operation allowsthe outputs sp1 through spN and the outputs sq1 through sqN to besequentially supplied to the ADC 8 via the first and second analogintegrators 6 and the switch 7. The analog integrators 6 for all thesense lines operate in parallel in accordance with the driving of thedrive lines.

The AD converter 8 carries out an AD conversion with respect to theoutputs from each capacitance column, the outputs each having beenintegrated by a corresponding one of the analog integrators 6, andsupplies the resulting outputs to the inner product computing section 9.

The inner product computing section 9 estimates, with reference to datastored in the RAM 10, (i) a capacitance value in the first capacitancecolumn, the capacitance value corresponding to a k1-th drive line (where1≦k1<M), by computing an inner product of a corresponding output sFirstand a corresponding code sequence di and (ii) a capacitance value in thesecond capacitance column, the capacitance value corresponding to ak2-th drive line (where k1<k2, and 1<k1≦M), by computing an innerproduct of a corresponding output sSecond and a corresponding codesequence di.

The application processing section 11 carries out a gesture recognitionprocess on the basis of capacitance values of the capacitances whichcapacitance values have been estimated by the inner product computingsection 9, and thus generates a gesture command.

(Specific Examples of Code Sequences)

FIG. 5 is a diagram illustrating a first specific example of orthogonalcode sequences as an input to the sensor panel 2. The orthogonal codesequences di each with a length N can be created specifically asdescribed below, for example.

An Hadamard matrix, which is a typical example of orthogonal codesequences, is created by Sylvester method illustrated in FIG. 5. Themethod first creates a building block of 2 rows×2 columns as a basicstructure. The building block includes four bits, among which an upperright one, an upper left one, and a lower left one are identical to oneanother, whereas a lower right one is an inverse of the above bits.

The method then combines four blocks of the above 2×2 basic structure atupper right, upper left, lower right, and lower left locations so as tocreate codes in a bit arrangement of 4 rows×4 columns. The method alsoinverts bits in the lower right block as in the above creation of a 2×2building block. Next, the method similarly creates codes in a bitarrangement of 8 rows×8 columns, and then creates codes in a bitarrangement of 16 rows×16 columns. These matrices each satisfy theabove-mentioned definition of being “orthogonal” in the presentinvention.

In a case where, for example, the sensor panel 2 of the presentembodiment includes 16 drive lines, the present embodiment can use, asthe orthogonal code sequences, codes in a bit arrangement of 16 rows×16columns illustrated in FIG. 5. An Hadamard matrix is a square matrixwhich includes elements each being 1 or −1 and which includes rowsorthogonal to one another. In other words, any two rows in an Hadamardmatrix represent vectors perpendicular to each other.

The orthogonal code sequences of the present embodiment can be any M-rowmatrix taken from an N-dimensional Hadamard matrix (where M≦N). Asdescribed below, an Hadamard matrix created by a method other thanSylvester method can alternatively be used in the present invention.

FIG. 6 is a diagram illustrating a second specific example of theorthogonal code sequences. FIG. 7 is a diagram illustrating a thirdspecific example of the orthogonal code sequences. While anyN-dimensional Hadamard matrix created by Sylvester method can beexpressed by a power of N=2, it is assumed that an Hadamard matrix canbe created if N is a multiple of 4. For example, FIG. 6 illustrates anHadamard matrix in which N=12, whereas FIG. 7 illustrates an Hadamardmatrix in which N=20. These Hadamard matrices created by a method otherthan Sylvester method can alternatively be used as the orthogonal codesequences of the present embodiment.

(How Inner Product is Computed)

An inner product matrix C′ij=di·sj is computed through steps describedbelow.

(1) The integrated circuit 3 resets an inner product matrix stored inthe RAM 10 (see FIG. 2) of the estimation section 5 to C′ij=0.

(2) The drive section 4 drives an i-th drive line DLi (where i=1, . . ., M) at a voltage V×dik in parallel at a time tk (where k is one of 1, .. . , N) so as to supply each connected capacitance with an electriccharge Cij×V×dik.

(3) The integrated circuit 3 connects the analog integrators 6 to theircorresponding sense lines j (where j=1, . . . , L) so that the analogintegrators 6 each read out an output voltage sjk from a correspondingone of the capacitances which have been charged at the time tk. Theswitch 7 then sequentially supplies the L output voltages sjk for thetime tk to the AD converter 8 for AD conversion. The L output voltagessjk have been read out by the L respective analog integrators 6 providedso as to correspond to the L sense lines. The AD converter 8 carries outan AD conversion with respect to the output voltages sjk for the timetk, and then supplies them to the inner product computing section 9. Theoutput voltages sjk for the time tk thus supplied to the inner productcomputing section 9 are expressed as follows:

${sjk} = {\sum\limits_{i = 1}^{M}{\left( {{Cij} \times V \times {{dik}/C}\mspace{11mu}{int}} \right).}}$

(4) The inner product computing section 9 carries out addition orsubtraction with respect to C′ij in accordance with (i) the L respectiveoutput voltages sjk outputted from the AD converter 8 and (ii) codesequences dik stored in the RAM 10. Specifically, the inner productcomputing section 9 carries out addition if a code sequence dik inquestion is 1, whereas it carries out subtraction if a code sequence dikin question is −1. The inner product computing section 9 then updatesvalues of C′ij on the basis of results of the addition or subtraction:C′ij←C′ij+dik×sjk

(5) The above procedure is repeated N times so as to correspond to thelength of each code sequence while a value of the time is increased inincrements (that is, tk+1). The process then returns to the step (1).

Completing the above steps causes C′ij to have values equal to resultsof the inner product computation.

The sensor panel 2 of the present embodiment, as described above,includes M drive lines and L sense lines, and has a length N for eachcode sequence. In a case where, for example, the sensor panel 2 is usedin a 4-inch class mobile data terminal or the like, the sensor panel 2will have a pitch of approximately 3 mm if M=16 and L=32. In a casewhere, for example, the sensor panel 2 is used in an electronic deviceincluding a 20-inch class screen, the sensor panel 2 will have a pitchof approximately 6 mm if M=48 and L=80. The length N of the codesequences has a very large degree of freedom, for example, N=64 to 512.

(Difference in Concept of Driving Between Present Invention andConventional Art)

The capacitance detecting circuit disclosed in Patent Literature 2mentioned above also (i) drives drive lines on the basis of a codesequence, (ii) outputs measured voltages each obtained by convertinginto an electric signal a sum total of currents across capacitances,connected to sense lines, at a plurality of respective intersections ofeach sense line with the driven drive lines, and (iii) carries out, foreach sense line, a product-sum operation on the basis of the measuredvoltages and the code sequence. The capacitance detecting circuit thusfinds a voltage value corresponding to each of the capacitances at therespective intersections. This capacitance detecting circuit, however,differs as below from the present embodiment in concept of driving thedrive lines.

To simplify an explanation, the following description deals with anexample case in which four capacitances (C1, C2, C3, and C4) are formedbetween a single sense line and four drive lines. Assuming that drivingsignals (code sequences) for the four drive lines are 1, 1, −1, and −1(1, 1, 0, and 0 in Patent Literature 2), the present embodiment drivesall the drive lines for each driving operation and thus produces anintegral output corresponding toC1+C2−C3−C4  (Formula 3),whereas the capacitance detecting circuit disclosed in Patent Literature2 drives only drive lines corresponding to “1” and thus produces anintegral output corresponding toC1+C2  (Formula 4).Comparison between Formula 3 of the present embodiment and Formula 4 ofPatent Literature 2 shows that the integral output produced in thepresent embodiment has a larger amount of information than that ofPatent Literature 2.

Assuming thatCi=C+ΔCiwhere ΔCi represents a change in capacitance (ΔCi is normallyapproximately 10% of C),

$\begin{matrix}{\begin{matrix}{\left( {{Formula}\mspace{14mu} 3} \right) = {{C\; 1} + {C\; 2} - {C\; 3} - {C\; 4}}} \\{= {{\Delta\; C\; 1} + {\Delta\; C\; 2} - {\Delta\; C\; 3} - {\Delta\; C\; 4}}} \\{{\approx {0.2 \times C}},}\end{matrix}{and}} & \left( {{Formula}\mspace{14mu} 5} \right) \\\begin{matrix}{\left( {{Formula}\mspace{14mu} 4} \right) = {{2 \times C} + {\Delta\; C\; 1} + {\Delta\; C\; 2}}} \\{{\approx {2 \times C}},}\end{matrix} & \left( {{Formula}\mspace{14mu} 6} \right)\end{matrix}$where the symbol “≈” means “nearly equal.”

Since ΔCi is approximately 10% of C in a touch sensor panel or the like,Formula 6 yields a value which is approximately 10 times as large as avalue of Formula 5. This indicates that an integrating circuit thatsatisfies Formula 6 of Patent Literature 2 is unfortunately (i) requiredto set a gain which is approximately 1/10 of that of an integratingcircuit of the present embodiment which integrating circuit satisfiesFormula 5, and is thus (ii) lower in S/N ratio than the integratingcircuit of the present embodiment. This difference in S/N ratio furtherincreases with an increase in the number M of the drive lines.

The present embodiment, which drives all the drive lines in parallel foreach driving operation, differs from the capacitance detecting circuitdisclosed in Patent Literature 2, which switches between driving a firstdrive line group (C1 and C2) and driving a second drive line group (C3and C4) on the basis of a code sequence so as to cancel an offset errorin a measured voltage. In the present embodiment, an offset due tofeedthrough in a reset switch can be measured on the basis of an outputobtained from the AD converter 8 in a state where no signal is beinginputted to a drive line (that is, the drive line is driven at a voltageVref). Subtracting a measured offset value in a digital circuit cancelsan offset error.

(Difference in Positive and Negative Operation Between Present Inventionand Conventional Art)

The present embodiment calculates a value of Formula 3 at once bydriving the M drive lines in parallel in accordance with values in acode sequence, that is, by driving the M drive lines so that voltages +Vand −V are applied to the capacitances so as to correspond to +1 and −1,respectively. The capacitance detecting circuit disclosed in PatentLiterature 2, in contrast, first calculates C1+C2 of Formula 4 and thencalculates C3+C4 thereof. The capacitance detecting circuit of PatentLiterature 2 thus carries out a two-stage operation and is lesseffective in simultaneously achieving a high speed operation and powerconsumption reduction.

The present embodiment further differs from the capacitance detectingcircuit of Patent Literature 2 in that the present embodiment drives thedrive lines so that a voltage −V is applied so as to correspond to avalue of −1 in a code sequence, whereas the capacitance detectingcircuit of Patent Literature 2 merely drives the drive lines at avoltage +V and thus lacks a concept of driving the drive lines at avoltage −V.

(Another Configuration of Estimation Section 5)

The present embodiment describes an example arrangement including (i)analog integrators 6 which are provided so as to correspond to Lrespective sense lines, (ii) a switch 7 which sequentially selects oneof the analog integrators 6, (iii) a single AD converter 8, and (iv) asingle inner product computing section 9. The present invention is,however, not limited to this arrangement. The present invention canalternatively include a single analog integrator 6 so that the singleanalog integrator 6 sequentially selects an input to read out a signalfor each sense line.

The present invention can further alternatively include (i) ADconverters 8 provided so as to correspond to the respective sense linesand the respective analog integrators 6 and (ii) a switch 7 providedbetween the AD converters 8 and the inner product computing section 9.

(Variation of Present Embodiment)

The present embodiment describes an example case of detectingcapacitance values of respective capacitances formed between drive linesand sense lines. The present invention is, however, not limited to this.The present invention is also applicable in, for example, an arrangementfor estimating values of respective linear devices formed between drivelines and sense lines. The present invention is further applicable in anarrangement for estimating a coefficient Ck corresponding to a k-thinput xk (k=1, . . . , M) of a system which includes M inputs xk and hasa linear input/output.

Furthermore, (i) the touch sensor system 1 of the present embodiment and(ii) a display panel placed over the sensor panel 2 of the touch sensorsystem 1 can be combined with each other so as to constitute anelectronic device. Alternatively, (i) the touch sensor system 1 and (ii)a display panel including the sensor panel 2 and having a function ofthe sensor panel 2 included in the touch sensor system 1 can be combinedwith each other so as to constitute an electronic device.

(Embodiment 2)

(Method for Driving Sensor Panel at Two Voltages)

FIG. 8 is a first timing chart illustrating a method for driving asensor panel 2 included in a touch sensor system 1 of Embodiment 2.

The method described in Embodiment 1 above with reference to FIG. 4 fordriving the sensor panel 2 drives the sensor panel 2 at three voltages,namely Vref, Vref+V, and Vref−V. The driving method of Embodiment 2, incontrast, drives the sensor panel 2 at two voltages V1 and V2.

Specifically, for a value of +1 in a code sequence, the method drives acorresponding drive line at (i) a voltage V1 when a corresponding one ofthe analog integrators 6 (see FIG. 1) is reset and at (ii) a voltage V2when an output is sampled from a capacitance connected to acorresponding sense line. Further, for a value of −1 in a code sequence,the method drives a corresponding drive line at (i) the voltage V2 whena corresponding one of the analog integrators 6 is reset and at (ii) thevoltage V1 when an output is sampled from a capacitance connected to acorresponding sense line.

More specifically, in an example illustrated in FIG. 8, the drive lineDL1, which corresponds to a code sequence having elements d11=+1 andd12=+1, is driven at (i) the voltage V1 when the analog integrators 6are reset, (ii) the voltage V2 when outputs are sampled, (iii) thevoltage V1 when the analog integrators 6 are reset next, and (iv) thevoltage V2 when outputs are sampled next. The drive line DL2, whichcorresponds to a code sequence having elements d21=+1 and d22=−1, isdriven at (i) the voltage V1 when the analog integrators 6 are reset,(ii) the voltage V2 when outputs are sampled, (iii) the voltage V2 whenthe analog integrators 6 are reset next, and (iv) the voltage V1 whenoutputs are sampled next.

The drive line DL3, which corresponds to a code sequence having elementsd31=−1 and d32=−1, is driven at (i) the voltage V2 when the analogintegrators 6 are reset, (ii) the voltage V1 when outputs are sampled,(iii) the voltage V2 when the analog integrators 6 are reset, and (iv)the voltage V1 when outputs are sampled next. The drive line DL4, whichcorresponds to a code sequence having elements d41=−1 and d42=+1, isdriven at (i) the voltage V2 when the analog integrators 6 are reset,(ii) the voltage V1 when outputs are sampled, (iii) the voltage V1 whenthe analog integrators 6 are reset next, and (iv) the voltage V2 whenoutputs are sampled next. The drive line DLM, which corresponds to acode sequence having elements dM1=−1 and dM2=+1, is driven at (i) thevoltage V2 when the analog integrators 6 are reset, (ii) the voltage V1when outputs are sampled, (iii) the voltage V1 when the analogintegrators 6 are reset next, and (iv) the voltage V2 when outputs aresampled next.

Assuming that V1=Vdd and V2=Vss, an output is expressed as(Cf/Cint)×(V1−V2)=(Cf/Cint)×(Vdd−Vss).In the method described in Embodiment 1 above with reference to FIG. 4for driving the sensor panel 2, if Vref=(Vdd−Vss)/2,V=(Vdd−Vss)/2since Vdd=Vref+V and Vss=Vref−V. This V is half an output in the exampleillustrated in FIG. 8. The driving method of Embodiment 2 illustrated inFIG. 8 thus (i) achieves a signal intensity which is twice as large as asignal intensity achieved by the driving method of Embodiment 1illustrated in FIG. 4, and consequently (ii) allows the capacitances toeach store an electric charge which is twice as large accordingly.

(Reading Out Offset)

FIG. 9 is a second timing chart illustrating a method for driving thesensor panel 2 included in the touch sensor system 1 of Embodiment 2.

The method drives the drive lines DL1 through DLM as illustrated in FIG.9 before it drives the drive lines DL1 through DLM in parallelillustrated in FIG. 4 or 8. Specifically, the method drives the drivelines DL1 through DLM at a constant voltage Vref both when the analogintegrators 6 are reset and when outputs are sampled, and thus suppliesno signals to the drive lines. The method in this state reads out offsetoutput values from the respective analog integrators 6 (see FIGS. 1 and2). The ADC 8 then carries out an AD conversion with respect to theoffset output values read out from the analog integrators 6 as above.The inner product computing section 9 next measures the offset outputvalues which have been subjected to an AD conversion in the ADC 8. Theoffset output values thus measured are each stored in the RAM 10 inassociation with a corresponding one of the sense lines SL1 through SLL.

(Offset Compensation Method)

The method next drives the drive lines DL1 through DLM in parallel asillustrated in FIG. 4 or 8, and causes each capacitance column to supplyoutputs to a corresponding analog integrator 6. The ADC 8 then carriesout an AD conversion with respect to the outputs from the capacitancecolumns which outputs have been received by the analog integrators 6,and thus supplies the resulting outputs to the inner product computingsection 9. The inner product computing section 9 next subtracts, for therespective sense lines SL1 through SLL, the offset output values storedin the RAM 10 from the outputs from the capacitance columns whichoutputs have been supplied from the ADC 8. This cancels an offset due tofeedthrough in a reset switch in each analog integrator 6.

The method can alternatively (i) repeat, a plurality of times, aprocedure of: driving the drive lines DL1 through DLM at a constantvoltage Vref both when the analog integrators 6 are reset and whenoutputs are sampled; reading out offset output values from therespective analog integrators 6; causing the ADC 8 to carry out an ADconversion with respect to the offset output values read out as above;and causing the inner product computing section 9 to measure theresulting offset output values, so as to measure a plurality of sets ofoffset output values, and (ii) finding averages of the offset outputvalues so as to store in the RAM 10 the average offset output valuesfrom which noise components included in the offset have been removed.The above plurality of times can, for example, be set to 16 times for 60Hz or 100 times for 240 Hz.

(Embodiment 3)

(Switching Gains of Analog Integrators)

FIG. 10 is a diagram illustrating a method for driving a sensor panel 2of Embodiment 3. Constituents of the present embodiment which areidentical to their respective equivalents in Embodiment 1 are eachassigned the same reference sign accordingly. Such constituents of thepresent embodiment are not described in detail here.

The present embodiment deals with an example which involves (i) a sensorpanel 2 including four drive lines DL1 through DL4 and four sense linesSL1 through SL4 and (ii) a code sequence based on a four-dimensionalHadamard matrix created by Sylvester method.

The present embodiment includes analog integrators 6A. The analogintegrators 6A each include: an operational amplifier with a first inputconnected to a reference voltage Vref; an integral capacitance Cintprovided between an output of the operational amplifier and a secondinput thereof; three other integral capacitances connected to theintegral capacitance in parallel; and three switches each providedbetween one of the three other integral capacitances and the output ofthe operational amplifier.

A code sequence based on a four-dimensional Hadamard matrix created bySylvester method includes elements such that a sum total of elementsalong a column direction is “4” for the first column and “0” for each ofthe second to fourth columns. Thus, a value obtained by adding outputsfrom a capacitance column is significantly greater when the drive linesare driven on the basis of the elements in the first column of the codesequence than when the drive lines are driven on the basis of theelements in one of the second to fourth columns of the code sequence.The value may exceed a capacity of a corresponding analog integrator 6Aand thus saturate the analog integrator 6A.

In view of this, when the drive lines are driven on the basis of acolumn having a sum total of elements present in the code sequence alongthe column direction which sum total is so large as to saturate acorresponding analog integrator 6A, the switches included in thecorresponding analog integrator 6A are appropriately turned on so as toprevent saturation of the analog integrator 6A.

An Hadamard matrix created by Sylvester method invariably includes afirst column having elements each being +1. An Hadamard matrix thus hasa sum total of elements in the first column which sum total issignificantly greater than that in any other column, and may thussaturate a corresponding analog integrator 6A. It is, however, possibleto prevent such saturation of an analog integrator 6A by turning on theswitches in the analog integrator 6A as above so as to switch a gain ofthe analog integrator 6A.

As described above, Embodiment 3 switches a gain of each analogintegrator 6A in accordance with an absolute value of a sum total ofcorresponding elements present in the code sequence along the columndirection. As such, it is possible to prevent saturation of the analogintegrators 6A.

(Compensation of Gain Switching for Analog Integrator By Gain Switchingof Inner Product Computing Section)

The inner product computing section 9 estimates capacitance values in acapacitance column, the capacitance values corresponding to therespective drive lines, by computing an inner product of (i) a codesequence and (ii) digital values each obtained by an AD conversion, bythe ADC 8, of outputs from the capacitance column which outputs havebeen supplied to a corresponding one of the analog integrators 6A thatcan switch their respective gains. The inner product computing section 9switches weighting for each of the digital values in accordance with theabsolute value of a sum total of corresponding elements present in thecode sequence along the column direction. This makes equal, betweencolumns of the code sequence, a product of (i) the gain of an analogintegrator 6A and (ii) the gain obtained by weighting the digital value.

(Embodiment 4)

(Division for Driving Drive Lines a Plurality of Times) and ComputingInner Products

(a) and (b) of FIG. 11 are each a diagram illustrating a code sequencefor use in driving a sensor panel 2 of Embodiment 4.

(a) of FIG. 11 illustrates a code sequence based on a four-dimensionalHadamard matrix created by Sylvester method. The code sequence issimilar to the code sequence of FIG. 10 in that a sum total of elementsalong the column direction is “4” for the first column and “0” for eachof the second to fourth columns. Thus, a value of a sum total of outputsobtained from a capacitance column is significantly greater when thedrive lines are driven on the basis of the elements in the first columnof the code sequence than when the drive lines are driven on the basisof the elements in one of the second to fourth columns of the codesequence. The value may exceed a capacity of a corresponding analogintegrator 6A and thus saturate the analog integrator 6A.

In view of this, the present embodiment divides, as illustrated in (b)of FIG. 11, the first column (1, 1, 1, 1) of the code sequence into twocolumns: one column represented by (1, 1, 0, 0) and the other columnrepresented by (0, 0, 1, 1). This arrangement (i) increases the numberof driving operations for the four drive lines from 4 times to 5 timesand (ii) divides the sum total “4” of elements in the column directioninto “2” and “2.” The above arrangement thus reduces a maximum sum totalof elements in the column direction from “4” to “2,” and thus preventssaturation of the analog integrators.

Embodiment 4 illustrates an example code sequence based on afour-dimensional Hadamard matrix created by Sylvester method. Thepresent invention is, however, not limited to this. The presentinvention is alternatively applicable in a code sequence based on a2^(n)-dimensional Hadamard matrix other than a four-dimensional Hadamardmatrix. The present invention is also applicable in a code sequencebased on an Hadamard matrix of any dimension which Hadamard matrix iscreated by a method other than Sylvester method.

(Embodiment 5)

(Triangular Mountain Shaped Driving Method)

FIG. 12 is a diagram illustrating a code sequence for use in driving asensor panel 2 of Embodiment 5.

In the sensor panel 2 of Embodiment 5, M drive lines are driven inparallel for each capacitance column formed between the M drive linesand L sense lines. The M drive lines are driven as such on the basis ofcode sequences which are orthogonal to one another and include elementseach being +1 or −1 and each of which has a code length N>M. The codesequences correspond to respective rows of a 2^(n)-dimensional Hadamardmatrix (where M<2^(n)) created by Sylvester method. FIG. 12 illustratesan example of a code sequence of 13 rows×16 columns which is based on a16-dimensional Hadamard matrix and which corresponds to M drive lines(where M=13).

FIG. 13 is a graph illustrating a method for driving the sensor panel 2.The graph has (i) a horizontal axis representing a location, along thecolumn direction, in the Hadamard matrix (where N=16) illustrated inFIG. 12 and (ii) a vertical axis representing an absolute value of a sumtotal of elements present in the Hadamard matrix (where N=16) along thecolumn direction.

In the Hadamard matrix where N=16, elements in the first column are each“1.” Thus, a relation between (i) a location along the column direction(horizontal axis) and (ii) an absolute value of a sum total of elementsalong the column direction (vertical axis) is represented by a line L1,which shows a linear, monotone increase.

In the Hadamard matrix where N=16, the 9th column (that is, the(2⁽⁴⁻¹⁾+1)th column) includes “1” from the 1st row through to the 8throw and “−1” from the 9th row through to the 16th row. Thus, the aboverelation for the 9th column is represented by a line L2, which shows alinear, monotone increase and then a linear, monotone decrease, thusforming a triangular mountain shape with a base length of 16 and aheight of 8.

In the Hadamard matrix where N=16, the 5th column (that is, the(2⁴⁻¹−2⁴⁻²+1)-th column) includes (i) “1” from the 1st row through tothe 4th row, (ii) “−1” from the 5th row through to the 8th row, (iii)“1” from the 9th row through to the 12th row, and (iv) “−1” from the13th row through to the 16th row. Thus, the above relation for the 5thcolumn is represented by a line L3, which forms two triangular mountainshapes each with a base length of 8 and a height of 4. Further, the 13thcolumn (that is, the (2⁴⁻¹+2⁴⁻²+1)-th column) includes (i) “1” from the1st row through to the 4th row, (ii) “−1” from the 5th row through tothe 8th row, (iii) “−1” from the 9th row through to the 12th row, and(iv) “1” from the 13th row through to the 16th row. Thus, the aboverelation for the 13th column is also represented by the line L3, whichforms two triangular mountain shapes.

The 3rd column, the 7 column, the 11th column, and the 15th column areeach represented by a line L4, which forms four triangular mountainshapes each with a base length of 4 and a height of 2. The 2nd column,the 4th column, the 6th column, the 8th column, the 10th column, the12th column, the 14th column, and the 16th column are each representedby a line L5, which forms eight triangular mountain shapes each with abase length of 2 and a height of 1.

The description below supposes that the above absolute value of a sumtotal of elements present in the code sequence along the columndirection has a threshold Num, above which a corresponding analogintegrator 6 (see FIG. 1) is saturated. In the examples illustrated inFIGS. 12 and 13, Num=3, and the number of drive lines is 13 (M=13).

As illustrated in FIG. 13, the absolute value does not exceed thethreshold Num=3 in any column corresponding to the line L5 (that is, the2nd column, the 4th column, the 6th column, the 8th column, the 10thcolumn, the 12th column, the 14th column, and the 16th column) or anycolumn corresponding to the line L4 (that is, the 3rd column, the 7column, the 11 column, and the 15 column). Simultaneously driving the M(=13) drive lines thus does not saturate analog integrators 6corresponding to the above columns.

The 1st column corresponding to the line L1 exceeds the threshold Num=3.The 1st column is thus divided in driving on the basis of the thresholdNum=3 such that four sets each including three drive lines are drivensequentially from the 1st drive line, and the drive line DL13 is thendriven. This prevents saturation of the analog integrators 6.

In general terms, the above driving is carried out such that [M/Num]sets each including NuM drive lines are driven sequentially from the 1stdrive line through to the Num×[M/Num]-th drive line, and drive linescorresponding to a remainder of the (M/Num) are then driven in parallel.In the above description, [x] represents the integer part of x, whichalso applies in the description below.

The 9th column corresponding to the line L2 exceeds the threshold Num=3.For the 9th column corresponding to the line L2, the 2nd drive linethrough the 13th drive line are first driven in parallel in accordancewith their respective corresponding elements in the code sequence, andthe 1st drive line is then driven.

In general terms, the above driving is carried out such that a driveline on a row based on the (2^(n-1)−(M−2^(n-1)))-th row (=(2^(n)−M)-throw) through a drive line on the M-th row are first driven in parallel.Next, [row based on the (2^(n-1)−(M−2^(n-1))−1)-th row/Num] sets eachincluding Num drive lines are driven sequentially from the 1st driveline through to the drive line on the (2^(n-1)−(M−2^(n-1)))-th row(=(2^(n)−M)-th row). Then, drive lines other than the (row based on the(2^(n-1)−(M−2^(n-1))−1)-th row/Num) sets are driven in parallel.

In the example of Embodiment 5, where n=4 and M=13, the(2^(n-1)−(M−2^(n-1)))-th row=the 3rd row. Even in a case where the 3rddrive line through the 13th drive line are driven in parallel, a sumtotal of corresponding elements present in the code sequence along thecolumn direction is +1, which is 2 less than the threshold Num=3. Thus,even in a case where the 2nd drive line through the 13th drive line aredriven in parallel, a sum total of corresponding elements present in thecode sequence along the column direction is +2, which is still less thanthe threshold Num=3. As such, although the (2^(n-1)−(M−2^(n-1)))-th rowis the 3rd row, the 2nd row is selected as a row based on the(2^(n-1)−(M−2^(n-1)))-th row (=the 3rd row) in view of the thresholdNum, and the 2nd drive line through the 13th drive line are thus drivenin parallel.

The 5th column and the 13th column corresponding to the line L3 eachexceed the threshold Num=3. For the 5th column and the 13th columncorresponding to the line L3, the 1st drive line through the 8th driveline are first simultaneously driven in parallel. The 10th drive linethrough the 13th drive line are then driven. The 9th drive line isdriven next.

In general terms, the 1st drive line through the (2^(n-1))-th drive lineare first simultaneously driven in parallel. Next, a drive line on a rowbased on the ((2^(n-1)+2^(n-2))−(M−(2^(n-1)+2^(n-2))))-th row through adrive line on the M-th row are driven in parallel. Then, [((row based on((2^(n-1)+2^(n-2))−(M−(2^(n-1)+2^(n-2))))))−(2^(n-1)+1)/Num] sets eachincluding NuM drive lines are driven sequentially from the drive line onthe (2^(n-1)+1)-th row through to the drive line on the ((row based onthe ((2^(n-1)+2^(n-2))−(M−(2^(n-1)+2^(n-2)))-th row))−1)-th row. Next,drive lines other than the (((row based on((2^(n-1)+2^(n-2))−(M−(2^(n-1)+2^(n-2))))))−(2^(n-1)+1)/Num) sets aredriven in parallel.

In the example of Embodiment 5, where n=4 and M=13, the((2^(n-1)+2^(n-2))−(M−(2^(n-1)+2^(n-2))))-th row=the 11th row. Even in acase where the 11th drive line through the 13th drive line are driven inparallel, a sum total of corresponding elements present in the codesequence along the column direction is +1, which is 2 less than thethreshold Num=3. Thus, even in a case where the 10th drive line throughthe 13th drive line are driven in parallel, a sum total of correspondingelements present in the code sequence along the column direction is +2,which is still less than the threshold Num=3. As such, although the((2^(n-1)+2^(n-2))−(M−(2^(n-1)+2^(n-2))))-th row is the 11th row, the10th row is selected as a row based on the((2^(n-1)+2^(n-2))−(M−(2^(n-1)+2^(n-2))))-th row (=the 11th row) in viewof the threshold Num, and the 10th drive line through the 13th driveline are thus driven in parallel.

The following description deals with how the sensor panel 2 is driven ina case where the number of drive lines is 12 or smaller (M≦12). Thedescription below first deals with a case in which 8<M≦12: For each ofthe line L1 and the line L2, a driving method is identical to acorresponding one described above for the line L1 or the line L2. Forthe line L3, the drive line on the 1st row through a drive line on the(2^(n-1))-th row are first driven simultaneously in parallel. Next,[(M−(2^(n-1)))/Num] sets each including NuM drive lines are drivensequentially from a drive line on the ((2^(n-1))+1)-th row through to adrive line on the (2^(n-1))+Num×[(M−(2^(n-1)))/Num]-th row. Then, drivelines other than the ((M−(2^(n-1)))/Num) sets are driven in parallel.

The description below now deals with a case in which 4<M≦8: For the lineL1, a driving method is identical to that described above for the lineL1. For the line L2, a driving method is also identical to thatdescribed above for the line L1. For the line L3, a driving method isidentical to that described above for the line L2 of the case of M(number of drive lines)=13.

The description below deals with a case in which M<4: For the line L1, adriving method is identical to that described above for the line L1. Foreach of the line L2 and the line L3 also, a driving method is identicalto that described above for the line L1.

The following description deals with how the sensor panel 2 is driven ina case where the threshold Num=1 and M (number of drive lines)=13: Foreach of the line L1, the line L2, and the line L3, a driving method isidentical to a corresponding one described above for the case in whichthe threshold Num=3. For the line L4, a drive line on the 1st rowthrough a drive line on the (2^(n-1)+2^(n-2))-th row are first drivensimultaneously in parallel. Next, [(M−(2^(n-1)+2^(n-2)))/Num] sets eachincluding NuM drive lines are driven sequentially from a drive line onthe ((2^(n-1)+2^(n-2))+1)-th row through to a drive line on the(2^(n-1)+2^(n-2))+Num×[(M−(2^(n-1)+2^(n-2)))/Num]-th row. Then, drivelines other than the ((M−(2^(n-1)+2^(n-2)))/Num) sets are driven inparallel.

A driving method similar to the driving method described above cansimply be employed even in a case where the order of the2^(n)-dimensional Hadamard matrix (where M<2^(n)) is increased to n>4.

Even in a case where the relation between (i) a location in the codesequence along the column direction and (ii) the absolute value of a sumtotal of corresponding elements along the column direction is not asillustrated in FIG. 13, it is possible to switch rows of the codesequence to carry out the above driving method if such switching allowsa 2^(n)-dimensional Hadamard matrix (where M<2^(n)) to be created bySylvester method so as to satisfy the above relation illustrated in FIG.13.

Embodiments 1 through 5 above each describe an example of driving drivelines in parallel in accordance with orthogonal code sequences. Thepresent invention is, however, not limited to this. The presentinvention can alternatively drive drive lines in accordance with codesequences based on an M-sequence.

(a) of FIG. 14 is a diagram for explaining code sequences of the aboveEmbodiments which code sequences are based on an M-sequence. The codesequences di=(d₁₁, d₁₂, . . . d_(1N)), d₂=(d₂₁, d₂₂, . . . d_(2N)), . .. dM=(d_(M1), d_(M2), . . . d_(MN)) based on an M-sequence (i) serve todrive in parallel a first drive line through an M-th drive line and (ii)each include elements each being 1 or −1. The code sequences d₁, d₂, . .. dM based on an M-sequence, assuming that they are sequences resultingfrom circularly shifting an M-sequence each having a length N(=2^(n-1)), satisfy a condition defined by Formula 8 in (a) of FIG. 14.

An M-sequence is a type of binary pseudo-random number sequence, andincludes only two values, namely 1 and −1 (or 1 and 0). An M-sequencehas a cycle having a length represented by 2^(n-1). An M-sequence havinga length=2³−1=7 is, for example, “1, −1, −1, 1, 1, 1, −1.” An M-sequencehaving a length=2⁴−1=15 is, for example, “1, −1, −1, −1, 1, 1, 1, 1, −1,1, −1, 1, 1, −1, −1.”

(b) of FIG. 14 is a diagram illustrating a specific example of codesequences based on an M-sequence. (b) of FIG. 14 illustrates codesequences MCS based on an M-sequence which are code sequences of 13rows×15 columns. The code sequences MCS include a first row which is anM-sequence having a length=15, that is, “1, −1, −1, −1, 1, 1, 1, 1, −1,1, −1, 1, 1, −1, −1.” The code sequences MCS include a second row whichresults from circularly shifting the M-sequence on the first row to theleft by one element. The code sequences MCS include a third row whichresults from circularly shifting the M-sequence on the second row to theleft by one element. The circular shift continues in the following codesequences. The code sequences MCS thus include a k-th row which resultsfrom circularly shifting the M-sequence on the (k−1)-th row to the leftby one element (where 2≦k≦13).

(Embodiment 6)

(Electronic Device Including Touch Sensor System)

FIG. 15 is a functional block diagram illustrating a configuration of amobile telephone 12 including the touch sensor system 1. The mobiletelephone (electronic device) 12 includes: a CPU 15; a RAM 17; a ROM 16;a camera 21; a microphone 18; a loud speaker 19; operation keys 20; adisplay panel 13; a display control circuit 14; and the touch sensorsystem 1. The above constituents are interconnected via a data bus.

The CPU 15 controls operation of the mobile telephone 12. The CPU 15,for example, executes a program stored in the ROM 16. The operation keys20 receive an input of an instruction by a user of the mobile telephone12. The RAM 17 stores, in a volatile manner, data generated by executionof a program by the CPU 15 or data inputted with use of the operationkeys 20. The ROM 16 stores data in a nonvolatile manner.

The ROM 16 is a writable, erasable ROM such as EPROM (ErasableProgrammable Read-Only Memory) and a flash memory. The mobile telephone12 can further include an interface (IF; not shown in FIG. 15) forconnecting to another electronic device by wire.

The camera 21 photographs an object in response to an operation of theoperation keys 20 by the user. Image data of the object thusphotographed is stored in the RAM 17 or an external memory (for example,a memory card). The microphone 18 receives a speech input from the user.The mobile telephone 12 digitizes the speech input (analog data), andcan transmit the digitized speech input to a communication target (forexample, another mobile telephone). The loud speaker 19 outputs, forexample, sound based on data such as music data stored in the RAM 17.

The touch sensor system 1 includes a sensor panel 2 and an integratedcircuit 3. The CPU 15 controls operation of the touch sensor system 1.The CPU 15, for example, executes a program stored in the ROM 16. TheRAM 17 stores, in a volatile manner, data generated by execution of aprogram by the CPU 15. The ROM 16 stores data in a nonvolatile manner.

The display panel 13 displays, as controlled by the display controlcircuit 14, an image stored in the ROM 16 or the RAM 17. The displaypanel 13 either is placed on the sensor panel 2 or contains the sensorpanel 2.

(Embodiment 7)

(Configuration of Touch Sensor System)

FIG. 16 is a view schematically showing a configuration of a touchsensor system 101 in accordance with an embodiment. The touch sensorsystem 101 includes a touch panel 102. The touch panel 102 is providedso as to be stacked on a display panel 109. The touch panel 102 is forexample a large touch panel, which is approximately 80 inches in sizeand is capable of being placed on a surface of a board of an electronicblackboard system. The touch panel 102 may be contained in the displaypanel 109.

The touch panel 102 has on its surface a two-dimensional region 112. Thetwo-dimensional region 112 is made up of (i) a hand placing region(partial region) (also referred to as a hand placing pad) 113 that isrectangle in shape and (ii) a remainder region 114 that is other thanthe hand placing region 113.

FIG. 17 is a view showing the hand placing region 113 which is set onthe touch panel 102. The hand placing region 113 is rectangle in shape,and is set (i) so as to include a region 116 d of a hand that is placedon the touch panel 102 and a region 117 where a finger is in contactwith the touch panel 102 and (ii) such that a stylus input region 118where a tip of a stylus held in the hand is in contact with the touchpanel 102 is located outside the hand placing region 113. As describedabove, the hand placing region 113 is configured so as to include theregion 116 d where a hand holding an input stylus is placed.

The touch panel 102 includes a plurality of drive lines (notillustrated) arranged horizontally and in parallel with each other, aplurality of sense lines (not illustrated) arranged vertically and inparallel with each other, and a plurality of capacitances (notillustrated) formed at respective intersections of the plurality ofdrive lines and the plurality of sense lines.

The touch sensor system 101 includes a control circuit 115. The controlcircuit 115 has a driver 105 and a sense amplifier 106. The driver 105applies voltages to drive the plurality of drive lines, therebysupplying charges to the capacitances. The sense amplifier 106 reads outa linear sum of charges stored in the capacitances from each of thesense lines, and supplies the linear sum to an AD converter 107.

The AD converter 107 converts, from analogue to digital, the linear sumof the charges stored in the capacitances, and supplies it to a decodingsection 108. The decoding section 108 (i) decodes the linear sum of thecharges supplied from the AD converter 107 to find how capacitances aredistributed, (ii) generates a hand placing region touch signal (partialregion touch signal) corresponding to a touch to the hand placing region113 of the two-dimensional region 112 of the touch panel 102 and thensupplies the hand placing region touch signal to a hand placing regionprocessing section 103 (first processing means), and (iii) generates aplot signal (remainder region touch signal) corresponding to a touch tothe remainder region 114 and then supplies the plot signal to a plotinput processing section 104 (second processing means). The plot signalis typically a signal for input of a character being plotted.

The plot input processing section 104 carries out, in accordance withthe plot signal supplied from the decoding section 108, a process basedon a plot input with respect to the remainder region 114 of thetwo-dimensional region 112.

The hand placing region processing section 103 carries out, inaccordance with the hand placing region touch signal supplied from thedecoding section 108, a process related to movement of the hand placingregion 113 or a change in size of the hand placing region 113.

With such a configuration in which the hand placing region 113 where atouch with a hand to the touch panel 102 is not regarded as a stylusinput signal (plot signal) is set so that only a signal generated by atouch to the remainder region 114 that is other than the hand placingregion 113 is regarded as a stylus input signal, it is possible toprevent a signal based on an unintended touch input with respect to thehand placing region 113 from being falsely recognized as a signal basedon an intended input with a stylus with respect to the remainder region114.

(How to Set Hand Placing Region)

(a) and (b) of FIG. 18 and (a) and (b) of FIG. 19 are views showing anexample of how the hand placing region 113 is set by a user. The controlcircuit 115 includes a hand placing region setting section 110.

As shown in (a) of FIG. 18, a user touches with a finger a hand placingpad menu 119 on an application screen displayed on the display panel109, and moves the finger to the center of the screen. In response tothis, the hand placing region setting section 110 gives, to the handplacing region processing section 103, an instruction to move a displayposition of the hand placing region 113 to the center of the screen.Then, when the user touches a corner of the hand placing region 113 thusmoved to the center of the screen, the hand placing region settingsection 110 gives, to the hand placing region processing section 103, aninstruction to change the size of the hand placing region 113 accordingto how the corner is touched (refer to (b) of FIG. 18). Further, whenthe user touches the center of the hand placing region 113 displayed onthe display panel 119 and moves the finger while keeping the finger incontact with the display panel 119, the hand placing region settingsection 110 gives, to the hand placing region processing section 103, aninstruction to change the display position of the hand placing region113 according to the movement of the finger (refer to (a) of FIG. 19).

As described above, it is possible to set the hand placing region 113from a menu of application displayed on the display panel 109 by a touchoperation, and further possible to change the position and the size ofthe hand placing region 113 by a touch operation.

For easy handwriting input with use of a stylus, the hand placing regionsetting section 110 may give, to the hand placing region processingsection 103, an instruction to move the hand placing region 113 so thatthe hand placing region 113 follows movement of a hand that holds astylus corresponding to a stylus input trail 120 and is placed on thetouch panel (see (b) of FIG. 19). This can be achieved by for example(i) finding a center of mass of the region 116 d (FIG. 17) which is inthe hand placing region 113 and in which a touch signal is generated and(ii) moving the hand placing region 113 so that the hand placing region113 follows movement of the center of mass.

Further, the control circuit 115 may include an automatic settingsection (automatic setting means) 111 for automatically setting theposition and the size of the hand placing region 113 in accordance withthe hand placing region touch signal and the plot signal.

It is also possible to employ a configuration in which a plurality ofhand placing regions 113 are set. This is because a large-screen touchsensor system would receive inputs with styluses from a plurality ofusers.

In the present embodiment, a capacitive touch sensor system is discussedas an example. Note, however, that the present invention is not limitedto this, and is applicable also to a touch sensor system other than thecapacitive touch sensor system. For example, the present invention isapplicable to an electromagnetic induction touch sensor system.

Further, although the hand placing region 113 rectangle in shape isdiscussed as an example, the present invention is not limited to this.The hand placing region 113 may have a shape other than a rectangle, forexample a circle, an ellipse or a triangle.

Further, a menu selection processing section and an icon movementprocessing section may be provided as the second processing meansrecited in claims, in addition to the plot input processing section 104.The menu selection processing section processes a touch signal forselecting a menu displayed in the remainder region 114, and the iconmovement processing section processes a touch signal for moving an icondisplayed in the remainder region 114. Further, a blackboard eraserregion may be provided in the two-dimensional region 112 of the touchpanel 102 as the partial region recited in claims instead of or inaddition to the hand placing region 113, and a blackboard eraserprocessing section may be provided as the first processing means recitedin claims. The blackboard eraser region serves as a blackboard eraser(or an eraser), and the blackboard eraser processing section carries outa function of the blackboard eraser region as a blackboard eraser inaccordance with a signal from the blackboard eraser region.

A signal (remainder region touch signal) corresponding to a touch to theremainder region 114 includes (i) a plot signal generated with use of astylus and/or (ii) a touch signal generated with a finger. The plotsignal generated with use of a stylus includes: a signal generated inresponse to an operation to plot a character on the remainder region 114with use of a stylus; a signal generated in response to an operation toselect, with use of a stylus, a menu displayed on the remainder region114; and a signal generated in response to an operation to select ormove, with use of a stylus, an icon displayed on the remainder region114. The touch signal generated with a finger includes: a signalgenerated in response to an operation to plot a character on theremainder region 114 with a finger; a signal generated in response to anoperation to select, with a finger, a menu displayed on the remainderregion 114; and a signal generated in response to an operation to selector move, with a finger, an icon displayed on the remainder region 114.

A linear system coefficient estimating method of the present inventionincludes the steps of: (A) (a) inputting, on a basis of M code sequencesdi (=di1, di2, . . . , diN, where i=1, . . . , M) which are orthogonalto one another and each of which has a length N, M inputs Xk (k=1, . . ., M) to a system which has a linear input and output and to which the Minputs Xk (k=1, . . . , M) are to be inputted, the system beingrepresented by

${{F\left( {{X\; 1},\ldots\mspace{14mu},{X\; M}} \right)} = {\sum\limits_{i = 1}^{M}\left( {{Ci} \times {Xi}} \right)}},$and (b) outputting N outputs s=(s1, s2, . . . , sN)=(F (d11, d21, . . ., dM1), F (d12, d22, . . . , dM2), . . . , F (d1N, d2N, . . . , dMN));and (B) estimating, on a basis of an inner product operation of theoutputs s and the code sequences di, a coefficient Ck corresponding to ak-th input Xk.

With the above feature, the linear system coefficient estimating methodinputs M inputs Xk (k=1, . . . , M) on the basis of M code sequences di(=di1, di2, . . . , diN, where i=1, . . . , M) which are orthogonal toone another and each of which has a length N and outputs N outputss=(s1, s2, . . . , sN)=(F (d11, d21, . . . , dM1), F (d12, d22, . . . ,dM2), . . . , F (diN, d2N, . . . , dMN)). The linear system coefficientestimating method thus estimates a coefficient Ck of the linear systemby simultaneously inputting all the M inputs. The linear systemcoefficient estimating method consequently (i) eliminates the need tosequentially select one of M inputs and scan it for an input as inconventional arrangements and (ii) even with an increase in the number Mof inputs, does not shorten a process time for obtaining a coefficientvalue of the linear system. The linear system coefficient estimatingmethod thus maintains a good detection accuracy and achieves a goodresolution and a high-speed operation.

Another linear system coefficient estimating method of the presentinvention includes the steps of: (A) (a) inputting, on a basis of M codesequences di (=di1, di2, . . . , diN, where i=1, . . . , M) which areorthogonal to one another and each of which has a length N, M inputs Xk(k=1, . . . , M) to each of a first system and a second system each ofwhich has a linear input and output and to each of which the M inputs Xk(k=1, . . . , M) are to be inputted, the first and second systems beingrepresented by

${F\; 1\left( {{X\; 1},\ldots\mspace{14mu},{X\; M}} \right)} = {\sum\limits_{i = 1}^{M}\left( {C\; 1i \times {Xi}} \right)}$${{F\; 2\left( {{X\; 1},\ldots\mspace{14mu},{X\; M}} \right)} = {\sum\limits_{i = 1}^{M}\left( {C\; 2i \times {Xi}} \right)}},$and (b) outputting N outputs sFirst=(s11, s12, . . . , s1N)=(F1 (d11,d21, . . . , dM1), F1 (d12, d22, . . . , dM2), . . . , F1 (diN, d2N, . .. , dMN)) from the first system and N outputs sSecond=(s21, s22, . . . ,s2N)=(F2 (d11, d21, . . . , dM1), F2 (d12, d22, . . . , dM2), . . . , F2(d1N, d2N, . . . , dMN)) from the second system; and (B) estimating (a)on a basis of a first inner product operation of the outputs sFirst andthe code sequences di, a coefficient C1k of the first system whichcoefficient C1k corresponds to a k1-th input Xk and (b) on a basis of asecond inner product operation of the outputs sSecond and the codesequences di, a coefficient C2k of the second system which coefficientC2k corresponds to a k2-th input Xk.

With the above feature, the linear system coefficient estimating methodinputs M inputs xk (k=1, . . . , M) on the basis of M code sequences di(=di1, di2, . . . , diN, where i=1, . . . , M) which are orthogonal toone another and each of which has a length N, and outputs N outputssFirst=(s11, s12, . . . , s1N)=(F1 (d11, d21, . . . , dM1), F1 (d12,d22, . . . , dM2), . . . , F1 (d1N, d2N, . . . , dMN)) from the firstsystem and N outputs sSecond=(s21, s22, . . . , s2N)=(F2 (d11, d21, . .. , dM1), F2 (d12, d22, . . . , dM2), . . . , F2 (d1N, d2N, . . . ,dMN)) from the second system. The linear system coefficient estimatingmethod thus estimates a coefficient C1k of the first system and acoefficient C2k of the second system by simultaneously inputting all theM inputs. The linear system coefficient estimating method consequently(i) eliminates the need to sequentially select one of M inputs and scanit for an input as in conventional arrangements and (ii) even with anincrease in the number M of inputs, does not shorten a process time forobtaining coefficient values of the first and second linear systems. Thelinear system coefficient estimating method thus maintains a gooddetection accuracy and achieves a good resolution and a high-speedoperation.

A linear device column value estimating method of the present inventionincludes the steps of: (A) (a) driving, on a basis of M code sequencesdi (=di1, di2, . . . , diN, where i=1, . . . , M) which are orthogonalto one another and each of which has a length N, M drive lines inparallel for each of (I) a first linear device column C1i (i=1, . . . ,M) formed between the M drive lines and a first sense line and (II) asecond linear device column C2i (i=1, . . . , M) formed between the Mdrive lines and a second sense line, and thus (b) outputting N outputssFirst=(s11, s12, . . . , s1N) from the first linear device column and Noutputs sSecond=(s21, s22, . . . , s2N) from the second linear devicecolumn; and (B) estimating (a) on a basis of a first inner productoperation of the outputs sFirst and the code sequences di, a firstlinear device value in the first linear device column which first lineardevice value corresponds to a k1-th drive line and (b) on a basis of asecond inner product operation of the outputs sSecond and the codesequences di, a second linear device value in the second linear devicecolumn which second linear device value corresponds to a k2-th driveline.

With the above feature, the linear device column value estimating method(a) drives M drive lines in parallel on the basis of M code sequences di(=di1, di2, . . . , diN, where i=1, . . . , M) which are orthogonal toone another and each of which has a length N, and (b) outputs N outputssFirst=(s11, s12, . . . , s1N) from the first linear device column and Noutputs sSecond=(s21, s22, . . . , s2N) from the second linear devicecolumn. The linear device column value estimating method thus estimates(a) a first linear device value in the first linear device column and(b) a second linear device value in the second linear device column bysimultaneously driving all the M drive lines. The linear device columnvalue estimating method consequently (i) eliminates the need tosequentially select one of M drive lines and scan it for an input as inconventional arrangements, and (ii) extends a process time for obtaininga first linear device value in the first linear device column and asecond linear device value in the second linear device column. Thelinear device column value estimating method thus maintains a gooddetection accuracy and achieves a good resolution and a high-speedoperation.

A capacitance detecting method of the present invention includes thesteps of: (A) (a) driving, on a basis of code sequences di (=di1, di2, .. . , diN, where i=1, . . . , M) which are orthogonal to one another andinclude elements each being either +1 or −1 and each of which has alength N, M drive lines in parallel for each of (I) a first capacitancecolumn C1i (i=1, . . . , M) formed between the M drive lines and a firstsense line and (II) a second capacitance column C2i (i=1, . . . , M)formed between the M drive lines and a second sense line, so that avoltage +V is applied for an element of +1 in the code sequences andthat a voltage −V is applied for an element of −1 in the code sequences,and thus (b) outputting outputs sFirst=(s11, s12, . . . , s1N) from thefirst capacitance column and outputs sSecond=(s21, s22, . . . , s2N)from the second capacitance column; and (B) estimating (a) on a basis ofa first inner product operation of the outputs sFirst and the codesequences di, a first capacitance value in the first capacitance columnwhich first capacitance value corresponds to a k1-th drive line and (b)on a basis of a second inner product operation of the outputs sSecondand the code sequences di, a second capacitance value in the secondcapacitance column which second capacitance value corresponds to a k2-thdrive line.

With the above feature, the capacitance detecting method (a) drives, onthe basis of code sequences di (=di1, di2, . . . , diN, where i=1, . . ., M) which are orthogonal to one another and include elements each beingeither +1 or −1 and each of which has a length N, M drive lines inparallel so that a voltage +V is applied for an element of +1 in thecode sequences and that a voltage −V is applied for an element of −1 inthe code sequences, and (b) outputs outputs sFirst=(s11, s12, . . . ,s1N) from the first capacitance column and outputs sSecond=(s21, s22, .. . , s2N) from the second capacitance column. The capacitance detectingmethod thus estimates, by simultaneously driving all the M drive lines,(a) a first capacitance value in the first capacitance column whichfirst capacitance value corresponds to the k1-th drive line and (b) asecond capacitance value in the second capacitance column which secondcapacitance value corresponds to the k2-th drive line. The capacitancedetecting method consequently (i) eliminates the need to sequentiallyselect one of M drive lines and scan it for an input as in conventionalarrangements, and (ii) extends a process time for obtaining (a) a firstcapacitance value in the first capacitance column which firstcapacitance value corresponds to the k1-th drive line and (b) a secondcapacitance value in the second capacitance column which corresponds tothe k2-th drive line. The capacitance detecting method thus maintains agood detection accuracy and achieves a good resolution and a high-speedoperation.

Further, the capacitance detecting method drives all the M drive linesin parallel each at either a voltage +V or a voltage −V in accordancewith the code sequences. The capacitance detecting method thus (i)increases an amount of information contained in output signals from acapacitance column and (ii) improves a S/N ratio, as compared to thearrangement of Patent Literature 2, which groups the drive lines fordriving in accordance with code sequences. The capacitance detectingmethod simply carries out a single-stage operation as compared to thearrangement of Patent Literature 2, which carries out a two-stageoperation, and is consequently advantageous in achieving a high-speedoperation.

An integrated circuit of the present invention includes: a drive sectionfor (a) driving, on a basis of code sequences di (=di1, di2, . . . ,diN, where i=1, . . . , M) which are orthogonal to one another andinclude elements each being either +1 or −1 and each of which has alength N, M drive lines in parallel for each of (I) a first capacitancecolumn C1i (i=1, . . . , M) formed between the M drive lines and a firstsense line and (II) a second capacitance column C2i (i=1, . . . , M)formed between the M drive lines and a second sense line, so that avoltage +V is applied for an element of +1 in the code sequences andthat a voltage −V is applied for an element of −1 in the code sequences,and thus (b) outputting outputs sFirst=(s11, s12, . . . , s1N) from thefirst capacitance column and outputs sSecond=(s21, s22, . . . , s2N)from the second capacitance column; and an estimation section forestimating (a) on a basis of a first inner product operation of theoutputs sFirst and the code sequences di, a first capacitance value inthe first capacitance column which first capacitance value correspondsto a k1-th drive line and (b) on a basis of a second inner productoperation of the outputs sSecond and the code sequences di, a secondcapacitance value in the second capacitance column which secondcapacitance value corresponds to a k2-th drive line.

With the above feature, the drive section (a) drives, on the basis ofcode sequences di (=di1, di2, . . . , diN, where i=1, . . . , M) whichare orthogonal to one another and include elements each being either +1or −1 and each of which has a length N, M drive lines in parallel sothat a voltage +V is applied for an element of +1 in the code sequencesand that a voltage −V is applied for an element of −1 in the codesequences, and thus (b) outputs outputs sFirst=(s11, s12, . . . , s1N)from the first capacitance column and outputs sSecond=(s21, s22, . . . ,s2N) from the second capacitance column. The integrated circuit thusestimates, by driving all the M drive lines, (a) a first capacitancevalue in the first capacitance column which first capacitance valuecorresponds to the k1-th drive line and (b) a second capacitance valuein the second capacitance column which second capacitance valuecorresponds to the k2-th drive line. The integrated circuit for use in acapacitance detecting method consequently (i) eliminates the need tosequentially select one of M drive lines and scan it for an input as inconventional arrangements, and (ii) extends a process time forestimating (a) a first capacitance value in the first capacitance columnwhich first capacitance value corresponds to the k1-th drive line and(b) a second capacitance value in the second capacitance column whichcorresponds to the k2-th drive line. The capacitance detecting methodthus maintains a good detection accuracy and achieves a good resolutionand a high-speed operation.

Further, the capacitance detecting method drives all the M drive linesin parallel each at either a voltage +V or a voltage −V in accordancewith the code sequences. The capacitance detecting method thus (i)increases an amount of information contained in output signals from acapacitance column and (ii) improves a S/N ratio, as compared to thearrangement of Patent Literature 2, which groups the drive lines fordriving in accordance with code sequences. The capacitance detectingmethod simply carries out a single-stage operation as compared to thearrangement of Patent Literature 2, which carries out a two-stageoperation, and is consequently advantageous in achieving a high-speedoperation.

A touch sensor system of the present invention includes: a sensor panelincluding (I) a first capacitance column C1i (i=1, . . . , M) formedbetween M drive lines and a first sense line and (II) a secondcapacitance column C2i (i=1, . . . , M) formed between the M drive linesand a second sense line; and an integrated circuit for controlling thesensor panel, the integrated circuit including: a drive section for (a)driving, on a basis of code sequences di (=di1, di2, . . . , diN, wherei=1, . . . , M) which are orthogonal to one another and include elementseach being either +1 or −1 and each of which has a length N, the M drivelines in parallel for each of (I) the first capacitance column C1i (i=1,. . . , M) and (II) the second capacitance column C2i (i=1, . . . , M)so that a voltage +V is applied for an element of +1 in the codesequences and that a voltage −V is applied for an element of −1 in thecode sequences, and thus (b) outputting outputs sFirst=(s11, s12, . . ., s1N) from the first capacitance column outputs sSecond=(s21, s22, . .. , s2N) from the second capacitance column; and an estimation sectionfor estimating (a) on a basis of a first inner product operation of theoutputs sFirst and the code sequences di, a first capacitance value inthe first capacitance column which first capacitance value correspondsto a k1-th drive line and (b) on a basis of a second inner productoperation of the outputs sSecond and the code sequences di, a secondcapacitance value in the second capacitance column which secondcapacitance value corresponds to a k2-th drive line.

With the above feature, the drive section (a) drives, on the basis ofcode sequences di (=di1, di2, . . . , diN, where i=1, . . . , M) whichare orthogonal to one another and include elements each being either +1or −1 and each of which has a length N, M drive lines in parallel sothat a voltage +V is applied for an element of +1 in the code sequencesand that a voltage −V is applied for an element of −1 in the codesequences, and thus (b) outputs outputs sFirst=(s11, s12, . . . , s1N)from the first capacitance column and outputs sSecond=(s21, s22, . . . ,s2N) from the second capacitance column. The touch sensor system thusestimates, by driving all the M drive lines, (a) a first capacitancevalue in the first capacitance column which first capacitance valuecorresponds to the k1-th drive line and (b) a second capacitance valuein the second capacitance column which second capacitance valuecorresponds to the k2-th drive line. The touch sensor systemconsequently (i) eliminates the need to sequentially select one of Mdrive lines and scan it for an input as in conventional arrangements,and (ii) extends a process time for estimating (a) a first capacitancevalue in the first capacitance column which first capacitance valuecorresponds to the k1-th drive line and (b) a second capacitance valuein the second capacitance column which corresponds to the k2-th driveline. The capacitance detecting method thus maintains a good detectionaccuracy and achieves a good resolution and a high-speed operation.

Further, the capacitance detecting method drives all the M drive linesin parallel each at either a voltage +V or a voltage −V in accordancewith the code sequences. The capacitance detecting method thus (i)increases an amount of information contained in output signals from acapacitance column and (ii) improves a S/N ratio, as compared to thearrangement of Patent Literature 2, which groups the drive lines fordriving in accordance with code sequences. The capacitance detectingmethod simply carries out a single-stage operation as compared to thearrangement of Patent Literature 2, which carries out a two-stageoperation, and is consequently advantageous in achieving a high-speedoperation.

An electronic device of the present invention includes: the touch sensorsystem of the present invention; and a display panel which either isplaced on the sensor panel included in the touch sensor system orcontains the sensor panel.

With the above feature, the drive section (a) drives, on the basis ofcode sequences di (=di1, di2, . . . , diN, where i=1, . . . , M) whichare orthogonal to one another and include elements each being either +1or −1 and each of which has a length N, M drive lines in parallel sothat a voltage +V is applied for an element of +1 in the code sequencesand that a voltage −V is applied for an element of −1 in the codesequences, and thus (b) outputs outputs sFirst=(s11, s12, . . . , s1N)from the first capacitance column and outputs sSecond=(s21, s22, . . . ,s2N) from the second capacitance column. The touch sensor system thusestimates, by driving all the M drive lines, (a) a first capacitancevalue in the first capacitance column which first capacitance valuecorresponds to the k1-th drive line and (b) a second capacitance valuein the second capacitance column which second capacitance valuecorresponds to the k2-th drive line. The electronic device including thetouch sensor system consequently (i) eliminates the need to sequentiallyselect one of M drive lines and scan it for an input as in conventionalarrangements, and (ii) extends a process time for estimating (a) a firstcapacitance value in the first capacitance column which firstcapacitance value corresponds to the k1-th drive line and (b) a secondcapacitance value in the second capacitance column which corresponds tothe k2-th drive line. The capacitance detecting method thus maintains agood detection accuracy and achieves a good resolution and a high-speedoperation.

Further, the capacitance detecting method drives all the M drive linesin parallel each at either a voltage +V or a voltage −V in accordancewith the code sequences. The capacitance detecting method thus (i)increases an amount of information contained in output signals from acapacitance column and (ii) improves a S/N ratio, as compared to thearrangement of Patent Literature 2, which groups the drive lines fordriving in accordance with code sequences. The capacitance detectingmethod simply carries out a single-stage operation as compared to thearrangement of Patent Literature 2, which carries out a two-stageoperation, and is consequently advantageous in achieving a high-speedoperation.

A capacitance detecting method of the present invention includes thesteps of: (A) (a) driving, on a basis of code sequences di (=di1, di2, .. . , diN, where i=1, . . . , M) which are orthogonal to one another andInclude elements each being either +1 or −1 and each of which has alength N, M drive lines in parallel for each of (I) a first capacitancecolumn Ci1 (i=1, . . . , M) formed between the M drive lines and a firstsense line and (II) a second capacitance column Ci2 (i=1, . . . , M)formed between the M drive lines and a second sense line, and thus (b)outputting, to an analog integrator, outputs sFirst=(s11, s12, . . . ,s1N) from the first capacitance column and outputs sSecond=(s21, s22, .. . , s2N) from the second capacitance column; and (B) estimating (a) ona basis of a first inner product operation of the outputs sFirst and thecode sequences di, a first capacitance value in the first capacitancecolumn which first capacitance value corresponds to a k1-th drive lineand (b) on a basis of a second inner product operation of the outputssSecond and the code sequences di, a second capacitance value in thesecond capacitance column which second capacitance value corresponds toa k2-th drive line, the step (A) driving, when the analog integrator isreset, the M drive lines at a first voltage represented by a voltageVref and driving, when the outputs sFirst and sSecond from the first andsecond capacitance columns are sampled, the M drive lines at (i) asecond voltage for an element of +1 in the code sequences, the secondvoltage being represented by a voltage (Vref+V), and (ii) a thirdvoltage for an element of −1 in the code sequences, the third voltagebeing represented by a voltage (Vref−V).

The above feature makes it possible to drive the drive lines in parallelwith use of a simple configuration on the basis of code sequences.

A capacitance detecting method of the present invention includes thesteps of: (A) (a) driving, on a basis of code sequences di (=di1, di2, .. . , diN, where i=1, . . . , M) which are orthogonal to one another andinclude elements each being either +1 or −1 and each of which has alength N, M drive lines in parallel for each of (I) a first capacitancecolumn Ci1 (i=1, . . . , M) formed between the M drive lines and a firstsense line and (II) a second capacitance column Ci2 (i=1, . . . , M)formed between the M drive lines and a second sense line, and thus (b)outputting, to an analog integrator, outputs sFirst=(s11, s12, . . . ,s1N) from the first capacitance column and outputs sSecond=(s21, s22, .. . , s2N) from the second capacitance column; and (B) estimating (a) ona basis of a first inner product operation of the outputs sFirst and thecode sequences di, a first capacitance value in the first capacitancecolumn which first capacitance value corresponds to a k1-th drive lineand (b) on a basis of a second inner product operation of the outputssSecond and the code sequences di, a second capacitance value in thesecond capacitance column which second capacitance value corresponds toa k2-th drive line, the step (A), for an element of +1 in the codesequences, driving the drive lines at (i) a first voltage when theanalog integrator is reset and (ii) a second voltage when the outputssFirst and sSecond from the first and second capacitance columns aresampled and, for an element of −1 in the code sequences, driving thedrive lines at (i) the second voltage when the analog integrator isreset and (ii) the first voltage when the outputs sFirst and sSecondfrom the first and second capacitance columns are sampled.

The above feature makes it possible to achieve a higher signal intensityand thus increase an electric charge stored in a capacitance.

A capacitance detecting method of the present invention includes thesteps of: (A) (a) driving, on a basis of code sequences di (=di1, di2, .. . , diN, where i=1, . . . , M) which are orthogonal to one another andinclude elements each being either +1 or −1 and each of which has alength N, M drive lines in parallel for each of (I) a first capacitancecolumn Ci1 (i=1, . . . , M) formed between the M drive lines and a firstsense line and (II) a second capacitance column Ci2 (i=1, . . . , M)formed between the M drive lines and a second sense line, and thus (b)outputting, to an analog integrator, outputs sFirst=(s11, s12, . . . ,s1N) from the first capacitance column and outputs sSecond=(s21, s22, .. . , s2N) from the second capacitance column; and (B) estimating (a) ona basis of a first inner product operation of the outputs sFirst and thecode sequences di, a first capacitance value in the first capacitancecolumn which first capacitance value corresponds to a k1-th drive lineand (b) on a basis of a second inner product operation of the outputssSecond and the code sequences di, a second capacitance value in thesecond capacitance column which second capacitance value corresponds toa k2-th drive line, the capacitance detecting method further including,before the step (A), the step of: (C) (a) driving, when the analogintegrator is reset and when the outputs sFirst and sSecond from thefirst and second capacitance columns are sampled, the drive lines at afirst voltage so that the outputs sFirst and sSecond from the first andsecond capacitance columns are outputted to the analog integrator, (b)reading out, from the analog integrator, the outputs sFirst and sSecondfrom the first and second capacitance columns as first offset outputsand second offset outputs, respectively, and (c) storing the first andsecond offset outputs in a memory.

The above feature makes it possible to cancel an offset caused by ananalog integrator.

An integrated circuit of the present invention includes: a drive sectionfor (a) driving, on a basis of code sequences di (=di1, di2, . . . ,diN, where i=1, . . . , M) which are orthogonal to one another andinclude elements each being either +1 or −1 and each of which has alength N, M drive lines in parallel for each of (I) a first capacitancecolumn Ci1 (i=1, . . . , M) formed between the M drive lines and a firstsense line and (II) a second capacitance column Ci2 (i=1, . . . , M)formed between the M drive lines and a second sense line, and thus (b)outputting, to an analog integrator, outputs sFirst=(s11, s12, . . . ,s1N) from the first capacitance column and outputs sSecond=(s21, s22, .. . , s2N) from the second capacitance column; and an estimation sectionfor estimating (a) on a basis of a first inner product operation of theoutputs sFirst and the code sequences di, a first capacitance value inthe first capacitance column which first capacitance value correspondsto a k1-th drive line and (b) on a basis of a second inner productoperation of the outputs sSecond and the code sequences di, a secondcapacitance value in the second capacitance column which secondcapacitance value corresponds to a k2-th drive line, the drive section,for an element of +1 in the code sequences, driving the drive lines at(i) a first voltage when the analog integrator is reset and (ii) asecond voltage when the outputs sFirst and sSecond from the first andsecond capacitance columns are sampled and, for an element of −1 in thecode sequences, driving the drive lines at (i) the second voltage whenthe analog integrator is reset and (ii) the first voltage when theoutputs sFirst and sSecond from the first and second capacitance columnsare sampled.

The above feature makes it possible to achieve a higher signal intensityand thus increase an electric charge stored in a capacitance.

An integrated circuit of the present invention includes: a drive sectionfor (a) driving, on a basis of code sequences di (=di1, di2, . . . ,diN, where i=1, . . . , M) which are orthogonal to one another andinclude elements each being either +1 or −1 and each of which has alength N, M drive lines in parallel for each of (I) a first capacitancecolumn Ci1 (i=1, . . . , M) formed between the M drive lines and a firstsense line and (II) a second capacitance column Ci2 (i=1, . . . , M)formed between the M drive lines and a second sense line, and thus (b)outputting, to an analog integrator, outputs sFirst=(s11, s12, . . . ,s1N) from the first capacitance column and outputs sSecond=(s21, s22, .. . , s2N) from the second capacitance column; and an estimation sectionfor estimating (a) on a basis of a first inner product operation of theoutputs sFirst and the code sequences di, a first capacitance value inthe first capacitance column which first capacitance value correspondsto a k1-th drive line and (b) on a basis of a second inner productoperation of the outputs sSecond and the code sequences di, a secondcapacitance value in the second capacitance column which secondcapacitance value corresponds to a k2-th drive line, the drive section,before outputting the outputs sFirst and sSecond from the first andsecond capacitance columns to the analog integrator, (a) driving, whenthe analog integrator is reset and when the outputs sFirst and sSecondfrom the first and second capacitance columns are sampled, the drivelines at a first voltage so that the outputs sFirst and sSecond from thefirst and second capacitance columns are outputted to the analogintegrator, (b) reading out, from the analog integrator, the outputssFirst and sSecond from the first and second capacitance columns asfirst offset outputs and second offset outputs, respectively, and (c)storing the first and second offset outputs in a memory.

The above feature makes it possible to cancel an offset caused by ananalog integrator.

A touch sensor system of the present invention includes: a sensor panelincluding (I) a first capacitance column Ci1 (i=1, . . . , M) formedbetween M drive lines and a first sense line and (II) a secondcapacitance column Ci2 (i=1, . . . , M) formed between the M drive linesand a second sense line; and an integrated circuit for controlling thesensor panel, the integrated circuit including: a drive section for (a)driving, on a basis of code sequences di (=di1, di2, . . . , diN, wherei=1, . . . , M) which are orthogonal to one another and include elementseach being either +1 or −1 and each of which has a length N, the M drivelines in parallel for each of (I) the first capacitance column Ci1 (i=1,. . . , M) and (II) the second capacitance column Ci2 (i=1, . . . , M),and thus (b) outputting, to an analog integrator, outputs sFirst=(s11,s12, . . . , s1N) from the first capacitance column and outputssSecond=(s21, s22, . . . , s2N) from the second capacitance column; andan estimation section for estimating (a) on a basis of a first innerproduct operation of the outputs sFirst and the code sequences di, afirst capacitance value in the first capacitance column which firstcapacitance value corresponds to a k1-th drive line and (b) on a basisof a second inner product operation of the outputs sSecond and the codesequences di, a second capacitance value in the second capacitancecolumn which second capacitance value corresponds to a k2-th drive line,the drive section, for an element of +1 in the code sequences, drivingthe drive lines at (i) a first voltage when the analog integrator isreset and (ii) a second voltage when the outputs sFirst and sSecond fromthe first and second capacitance columns are sampled and, for an elementof −1 in the code sequences, driving the drive lines at (i) the secondvoltage when the analog integrator is reset and (ii) the first voltagewhen the outputs sFirst and sSecond from the first and secondcapacitance columns are sampled.

The above feature makes it possible to achieve a higher signal intensityand thus increase an electric charge stored in a capacitance.

A touch sensor system of the present invention includes: a sensor panelincluding (I) a first capacitance column Ci1 (i=1, . . . , M) formedbetween M drive lines and a first sense line and (II) a secondcapacitance column Ci2 (i=1, . . . , M) formed between the M drive linesand a second sense line; and an integrated circuit for controlling thesensor panel, the integrated circuit including: a drive section for (a)driving, on a basis of code sequences di (=di1, di2, . . . , diN, wherei=1, . . . , M) which are orthogonal to one another and include elementseach being either +1 or −1 and each of which has a length N, the M drivelines in parallel for each of (I) the first capacitance column Ci1 (i=1,. . . , M) and (II) the second capacitance column Ci2 (i=1, . . . , M),and thus (b) outputting, to an analog integrator, outputs sFirst=(s11,s12, . . . , s1N) from the first capacitance column and outputssSecond=(s21, s22, . . . , s2N) from the second capacitance column; andan estimation section for estimating (a) on a basis of a first innerproduct operation of the outputs sFirst and the code sequences di, afirst capacitance value in the first capacitance column which firstcapacitance value corresponds to a k1-th drive line and (b) on a basisof a second inner product operation of the outputs sSecond and the codesequences di, a second capacitance value in the second capacitancecolumn which second capacitance value corresponds to a k2-th drive line,the drive section, before outputting the outputs sFirst and sSecond fromthe first and second capacitance columns to the analog integrator, (a)driving, when the analog integrator is reset and when the outputs sFirstand sSecond from the first and second capacitance columns are sampled,the drive lines at a first voltage so that the outputs sFirst andsSecond from the first and second capacitance columns are outputted tothe analog integrator, (b) reading out, from the analog integrator, theoutputs sFirst and sSecond from the first and second capacitance columnsas first offset outputs and second offset outputs, respectively, and (c)storing the first and second offset outputs in a memory.

The above feature makes it possible to cancel an offset caused by ananalog integrator.

An electronic device of the present invention includes: a touch sensorsystem of the present invention; and a display panel which either isplaced on the sensor panel included in the touch sensor system orcontains the sensor panel.

A capacitance detecting method of the present invention includes thesteps of: (A) (a) driving, on a basis of code sequences di (=di1, di2, .. . , diN, where i=1, . . . , M) which are orthogonal to one another andinclude elements each being either +1 or −1 and each of which has alength N, M drive lines in parallel for each of (I) a first capacitancecolumn Ci1 (i=1, . . . , M) formed between the M drive lines a firstsense line and (II) a second capacitance column Ci2 (i=1, . . . , M)formed between the M drive lines and a second sense line, so that avoltage +V is applied for an element of +1 in the code sequences andthat a voltage −V is applied for an element of −1 in the code sequences,and thus (b) outputting, to an analog integrator, outputs sFirst=(s11,s12, . . . , s1N) from the first capacitance column and outputssSecond=(s21, s22, . . . , s2N) from the second capacitance column; and(B) estimating (a) on a basis of a first inner product operation of theoutputs sFirst and the code sequences di, a first capacitance value inthe first capacitance column which first capacitance value correspondsto a k1-th drive line and (b) on a basis of a second inner productoperation of the outputs sSecond and the code sequences di, a secondcapacitance value in the second capacitance column which secondcapacitance value corresponds to a k2-th drive line, the step (A), toprevent saturation of the analog integrator, switching a gain of theanalog integrator in accordance with an absolute value of a sum total ofcorresponding elements present in the code sequences along a columndirection.

The above feature makes it possible to prevent saturation of an analogintegrator.

A capacitance detecting method of the present invention includes thesteps of: (A) (a) driving, on a basis of code sequences di (=di1, di2, .. . , diN, where i=1, . . . , M) which are orthogonal to one another andinclude elements each being either +1 or −1 and each of which has alength N, M drive lines in parallel for each of (I) a first capacitancecolumn Ci1 (i=1, . . . , M) formed between the M drive lines and a firstsense line and (II) a second capacitance column Ci2 (i=1, . . . , M)formed between the M drive lines and a second sense line, so that avoltage +V is applied for an element of +1 in the code sequences andthat a voltage −V is applied for an element of −1 in the code sequences,and thus (b) outputting, to an analog integrator, outputs sFirst=(s11,s12, . . . , s1N) from the first capacitance column and outputssSecond=(s21, s22, . . . , s2N) from the second capacitance column; and(B) estimating (a) on a basis of a first inner product operation of theoutputs sFirst and the code sequences di, a first capacitance value inthe first capacitance column which first capacitance value correspondsto a k1-th drive line and (b) on a basis of a second inner productoperation of the outputs sSecond and the code sequences di, a secondcapacitance value in the second capacitance column which secondcapacitance value corresponds to a k2-th drive line, the step (A), toprevent saturation of the analog integrator, dividing, in accordancewith an absolute value of a sum total of corresponding elements presentin the code sequences along a column direction, a column of the codesequences into a plurality of columns so as to divide the driving of theM drive lines into a plurality of drivings.

The above feature makes it possible to prevent saturation of an analogintegrator.

A capacitance detecting method of the present invention includes thesteps of: (A) (a) driving, on a basis of code sequences di (=di1, di2, .. . , diN, where i=1, . . . , M) which are orthogonal to one another andinclude elements each being +1 or −1 and each of which has a code lengthN=M, the code sequences di corresponding to respective rows of a2^(n)-dimensional Hadamard matrix created by Sylvester method, (M=2^(n))drive lines in parallel for each of (I) a first capacitance column Ci1(i=1, . . . , M) formed between the (M=2^(n)) drive lines and a firstsense line and (II) a second capacitance column Ci2 (i=1, . . . , M)formed between the (M=2^(n)) drive lines and a second sense line, sothat a voltage +V is applied for an element of +1 in the code sequencesand that a voltage −V is applied for an element of −1 in the codesequences, and thus (b) outputting, to an analog integrator, outputssFirst=(s11, s12, . . . , s1N) from the first capacitance column andoutputs sSecond=(s21, s22, . . . , s2N) from the second capacitancecolumn; and (B) estimating (a) on a basis of a first inner productoperation of the outputs sFirst and the code sequences di, a firstcapacitance value in the first capacitance column which firstcapacitance value corresponds to a k1-th drive line and (b) on a basisof a second inner product operation of the outputs sSecond and the codesequences di, a second capacitance value in the second capacitancecolumn which second capacitance value corresponds to a k2-th drive line,the step (A), to prevent saturation of the analog integrator, dividing afirst column of the code sequences into a plurality of columns so as todivide a driving for the first column of the code sequences into aplurality of drivings.

The above feature makes it possible to prevent saturation of an analogintegrator.

A capacitance detecting method of the present invention includes thesteps of: (A) (a) driving, on a basis of first code sequences di (=di1,di2, . . . , diN, where i=1, . . . , M) which are orthogonal to oneanother and include elements each being +1 or −1 and each of which has acode length N>M, the first code sequences di corresponding to respectiverows of a 2^(n)-dimensional (where M<2^(n)) Hadamard matrix created bySylvester method, M drive lines in parallel for each of (I) a firstcapacitance column Ci1 (i=1, . . . , M) formed between the M drive linesand a first sense line and (II) a second capacitance column Ci2 (i=1, .. . , M) formed between the M drive lines and a second sense line, sothat a voltage +V is applied for an element of +1 in the first codesequences that a voltage −V is applied for an element of −1 in the firstcode sequences, and thus (b) outputting, to an analog integrator,outputs sFirst=(s11, s12, . . . , s1N) from the first capacitance columnand outputs sSecond=(s21, s22, . . . , s2N) from the second capacitancecolumn; and (B) estimating (a) on a basis of a first inner productoperation of the outputs sFirst and the first code sequences di, a firstcapacitance value in the first capacitance column which firstcapacitance value corresponds to a k1-th drive line and (b) on a basisof a second inner product operation of the outputs sSecond and the firstcode sequences di, a second capacitance value in the second capacitancecolumn which second capacitance value corresponds to a k2-th drive line,the step (A) dividing a particular column of the first code sequencesinto a plurality of columns, the particular column having an absolutevalue of a sum total of corresponding elements present in the first codesequences along a column direction which absolute value exceeds athreshold Num for saturation of the analog integrator, so as to divide adriving for the particular column into a plurality of drivings.

The above feature makes it possible to prevent saturation of an analogintegrator in a driving based on a 2^(n)-dimensional (where M<2^(n))Hadamard matrix.

The linear system coefficient estimating method of the present inventioninputs M inputs xk (k=1, . . . , M) on the basis of M code sequences di(=di1, di2, . . . , diN, where i=1, . . . , M) which are orthogonal toone another and each of which has a length N and outputs N outputss=(s1, s2, . . . , sN)=(F (d11, d21, . . . , dM1), F (d12, d22, . . . ,dM2), . . . , F (d1N, d2N, . . . , dMN)). The linear system coefficientestimating method thus estimates a coefficient Ck of the linear systemby simultaneously inputting all the M inputs. The linear systemcoefficient estimating method consequently (i) eliminates the need tosequentially select one of M inputs and scan it for an input as inconventional arrangements and (ii) even with an increase in the number Mof inputs, does not shorten a process time for obtaining a coefficientvalue of the linear system. The linear system coefficient estimatingmethod thus maintains a good detection accuracy and achieves a goodresolution and a high-speed operation.

A touch sensor system in accordance with the present invention includes:a touch panel having a two-dimensional region made up of at least onepartial region and a remainder region that is other than said at leastone partial region; first processing means for carrying out a firstprocess in accordance with a partial region touch signal correspondingto a touch to said at least one partial region; and second processingmeans for carrying out a second process in accordance with a remainderregion touch signal corresponding to a touch to the remainder region,the second process being different in kind from the first process.

According to this feature, the first process is carried out inaccordance with the partial region touch signal corresponding to a touchto the partial region, and the second process that is different in kindfrom the first process is carried out in accordance with the remainderregion touch signal corresponding to a touch to the remainder region.This makes it possible to carry out processes in which (i) a signalbased on an unintended touch input with respect to the partial regionand (ii) a signal based on an intended touch input with respect to theremainder region are dealt with separately from each other.

As a result, it is possible to provide a touch sensor system that doesnot falsely recognize a signal based on an unintended touch input withrespect to the partial region as a signal based on an intended inputwith a stylus with respect to the remainder region.

A touch sensor system in accordance with the present invention includes:first processing means for carrying out a first process in accordancewith a partial region touch signal corresponding to a touch to the atleast partial region; and second processing means for carrying out asecond process in accordance with a remainder region touch signalcorresponding to a touch to the remainder region, the second processbeing different in kind from the first process. This makes it possibleto carry out processes in which (i) a signal based on an unintendedtouch input with respect to the partial region and (ii) a signal basedon an intended touch input with respect to the remainder region aredealt with separately from each other. As a result, it is possible toprovide a touch sensor system that does not falsely recognize a signalbased on an unintended touch input with respect to the partial region asa signal based on an intended input with a stylus with respect to theremainder region.

The linear device column value estimating method of the presentembodiment may preferably be arranged such that the code sequences di(=di1, di2, . . . , diN, where i=1, . . . , M) include elements each ofwhich is either +V or −V.

The above arrangement makes it possible to drive each drive line byapplying to it either a voltage +V or a voltage −V.

The capacitance detecting method of the present embodiment maypreferably be arranged such that the step (B) includes carrying out, foreach parallel driving based on the code sequences di, of addition orsubtraction in accordance with a code which addition or subtraction isnecessary for the first and second inner product operations.

The above arrangement carries out an inner product operation for eachparallel driving. The capacitance detecting method thus not only (i)allows pipeline processing and consequently carries out an operationwithin a short period of time, but also (ii) reduces an amount of memorynecessary to carry out an operation, as compared to an arrangement whichcarries out an inner product operation for each of N parallel drivingscorresponding to the length of the code sequences.

The capacitance detecting method may preferably be arranged such thatthe step (A) outputs the outputs sFirst from the first capacitancecolumn to a first analog integrator and the outputs sSecond from thesecond capacitance column to a second analog integrator; and the step(B) carries out (I) the first inner product operation by subjecting theoutputs sFirst, which have been outputted to the first analogintegrator, to an AD conversion in an AD converter and (II) the secondinner product operation by subjecting the outputs sSecond, which havebeen outputted to the second analog integrator, to an AD conversion inthe AD converter.

The above arrangement provides analog integrators in parallel for therespective sense lines, and thus increases a speed of detecting all thecapacitances provided in a matrix.

The capacitance detecting method may preferably be arranged such thatthe step (A) first outputs the outputs sFirst from the first capacitancecolumn to an analog integrator and second outputs the outputs sSecondfrom the second capacitance column to the analog integrator; and thestep (B) carries out (I) the first inner product operation by subjectingthe outputs sFirst, which have been outputted to the analog integrator,to an AD conversion in an AD converter and (II) the second inner productoperation by subjecting the outputs sSecond, which have been outputtedto the analog integrator, to an AD conversion in the AD converter.

The above arrangement allows a single analog integrator to carry out theestimating, and thus makes it possible to detect the capacitances withuse of a simpler configuration.

The capacitance detecting method may preferably be arranged such thatthe step (A) outputs the outputs sFirst from the first capacitancecolumn to a first analog integrator and the outputs sSecond from thesecond capacitance column to a second analog integrator; and the step(B) carries out (I) the first inner product operation by subjecting theoutputs sFirst, which have been outputted to the first analogintegrator, to an AD conversion in a first AD converter and (II) thesecond inner product operation by subjecting the outputs sSecond, whichhave been outputted to the second analog integrator, to an AD conversionin a second AD converter.

The above arrangement provides both analog integrators and AD convertersin parallel for the respective sense lines, and thus further increasesthe speed of detecting all the capacitances provided in a matrix.

The capacitance detecting method of the present embodiment maypreferably be arranged such that the step (B) estimates (a) the firstcapacitance value on a basis of a third inner product operation of (I) aresult obtained by subtracting, from the outputs sFirst, the firstoffset outputs stored in the memory and (II) the code sequences di and(b) the second capacitance value on a basis of a fourth inner productoperation of (I) a result obtained by subtracting, from the outputssSecond, the second offset outputs stored in the memory and (II) thecode sequences di.

The above arrangement makes it possible to cancel an offset caused by ananalog integrator.

The capacitance detecting method of the present embodiment maypreferably be arranged such that the step (C) (I) repeats a plurality oftimes an operation of (a) driving, when the analog integrator is resetand when the outputs sFirst and sSecond from the first and secondcapacitance columns are sampled, the drive lines at the first voltage sothat the outputs sFirst and sSecond from the first and secondcapacitance columns are outputted to the analog integrator and (b)reading out, from the analog integrator, the outputs sFirst and sSecondfrom the first and second capacitance columns as the first offsetoutputs and the second offset outputs, respectively, and (II) averages aplurality of sets of the first and second offset outputs read out andthen stores in the memory a result of the averaging.

The above arrangement makes it possible to store offset outputs in amemory after reducing a noise component contained in an offset caused byan analog integrator.

The capacitance detecting method of the present embodiment maypreferably be arranged such that the step (B) estimates (a) the firstcapacitance value on a basis of a third inner product operation of (I) afirst digital value obtained by an AD conversion of the outputs sFirstand (II) the code sequences di and (b) the second capacitance value on abasis of a fourth inner product operation of (I) a second digital valueobtained by an AD conversion of the outputs sSecond and (II) the codesequences di; and the step (B) switches weighting for each of the firstand second digital values in accordance with the absolute value of a sumtotal of corresponding elements present in the code sequences along thecolumn direction.

The above arrangement makes it possible to cause a gain obtained on apath from an analog integrator through to the inner product computingsection to be constant for each driving based on the code sequences.

The capacitance detecting method of the present embodiment maypreferably be arranged such that a column having an absolute value of asum total of corresponding elements present in the first code sequencesalong a column direction which absolute value exceeds a threshold Numfor saturation of the analog integrator corresponds to at least one of afirst column, a (2^(n-1)+1) column, a (2^(n-1)+2^(n-2)+1) column, and a(2^(n-1)−2^(n-2)+1) column of the 2^(n)-dimensional Hadamard matrix.

The above arrangement makes it possible to prevent, with use of a simplealgorithm, saturation of an analog integrator in a driving based on a2^(n)-dimensional (where M<2^(n)) Hadamard matrix.

The capacitance detecting method of the present embodiment maypreferably be arranged such that where [x] represents an integer part ofx, the step (A), in a case where the first column of the2^(n)-dimensional Hadamard matrix exceeds the threshold Num, first (a)sequentially drives [M/Num] sets each including Num drive lines from afirst drive line through to a Num×[M/Num]-th drive line and then (b)drives in parallel drive lines corresponding to a remainder of the(M/Num); the step (A), in a case where the (2^(n-1)+1) column of theHadamard matrix exceeds the threshold Num, first (a) drives in parallela drive line on a row based on a (2^(n-1)−(M−2^(n-1)))-th row through adrive line on an M-th row, second (b) sequentially drives [row based ona (2^(n-1)−(M−2^(n-1))−1)-th row/Num] sets each including Num drivelines from the drive line on a first row through to a drive line on therow based on a (2^(n-1)−(M−2^(n-1))−1)-th row, and third (c) drives inparallel drive lines corresponding to a remainder of the (row based on a(2^(n-1)−(M−2^(n-1))−1)-th row/Num); and the step (A), in a case wherethe (2^(n-1)+2^(n-2)+1) column of the Hadamard matrix exceeds thethreshold Num, first (a) simultaneously drives in parallel the driveline on the first row through a drive line on a (2^(n-1))-th row, second(b) drives in parallel a drive line on a row based on a((2^(n-1)+2^(n-2))−(M−(2^(n-1)+2^(n-2))))-th row through a drive line onthe M-th row, third (c) sequentially drives [(row based on(((2^(n-1)+2^(n-2))−(M−(2^(n-1)+2^(n-2))))))−(2^(n-1)+1)/Num] sets eachincluding NuM drive lines from a drive line on a (2^(n-1)+1)-th rowthrough to the drive line on the row based on the((2^(n-1)+2^(n-2))−(M−(2^(n-1)+2^(n-2))))-th row, and fourth (d) drivesin parallel drive lines corresponding to a remainder of the ((row basedon (((2^(n-1)+2^(n-2))−(M−(2^(n-1)+2^(n-2))))))−(2^(n-1)+1)/Num).

The above arrangement makes it possible to prevent, with use of a simplealgorithm, saturation of an analog integrator in a driving based on a2^(n)-dimensional (where M<2^(n)) Hadamard matrix.

The capacitance detecting method of the present embodiment maypreferably further include: the step of: creating, by switching rows,second code sequences based on the Hadamard matrix, wherein: the step(A) drives the M drive lines in parallel on a basis of the second codesequences.

The touch sensor system in accordance with the present embodiment ispreferably configured such that: said at least one partial region is ahand placing region that includes a region where a hand is placed forinput to the touch panel; the partial region touch signal is a handplacing region touch signal corresponding to a touch to the hand placingregion; the remainder region touch signal includes (i) a plot signalgenerated by a stylus and/or (ii) a touch signal generated by a finger;the first processing means carries out, in accordance with the handplacing region touch signal, a process related to movement of the handplacing region or to a change in size of the hand placing region; andthe second processing means carries out, in accordance with theremainder region touch signal, a process based on (a) a plot input withrespect to the two-dimensional region and/or (b) a touch input withrespect to the two-dimensional region.

The configuration makes it possible to carry out processes in which (i)an unintended touch signal generated by a hand that holds a stylus andis placed on the touch panel and (ii) an intended touch signal based onplotting with respect to the touch panel are dealt with separately fromeach other.

The touch sensor system in accordance with the present embodiment ispreferably configured such that the touch panel has: two-dimensionallydistributed capacitances; and a plurality of said hand placing regions.

The configuration causes the present invention to be applicable to atouch sensor system including a large-screen touch panel.

The touch sensor system in accordance with the present embodiment ispreferably configured such that the hand placing region moves within thetwo-dimensional region according to movement of the hand.

The configuration makes it possible to carry out processes in which (i)an unintended touch signal generated by a hand that holds a stylus andis placed on the touch panel at any position in the two-dimensionalregion and (ii) an intended touch signal based on plotting with respectto the touch panel are dealt with separately from each other.

The touch sensor system in accordance with the present embodiment ispreferably configured such that the hand placing region is rectangle inshape.

The configuration makes it possible to easily configure the hand placingregion.

It is preferable that a touch sensor system in accordance with thepresent embodiment further include: a display panel which is provided soas to be stacked on the touch panel or in which the touch panel iscontained; and hand placing region setting means for setting the handplacing region on a screen that is displayed on the display panel.

The configuration makes it possible to easily set the hand placingregion.

It is preferable that a touch sensor system in accordance with thepresent embodiment further include automatic setting means forautomatically setting the hand placing region in accordance with a touchto the two-dimensional region.

The configuration makes it possible to more easily set the hand placingregion.

The present invention is not limited to the description of theembodiments above, but may be altered in various ways by a skilledperson within the scope of the claims. Any embodiment based on a propercombination of technical means disclosed in different embodiments isalso encompassed in the technical scope of the present invention.

INDUSTRIAL APPLICABILITY

The present invention is applicable to a method for estimating ordetecting a coefficient, a device value, or a capacitance in a linearsystem configured in a matrix. The present invention is furtherapplicable to an integrated circuit, a touch sensor system, and anelectronic device each operating in accordance with the method. Thepresent invention is also applicable to a fingerprint detection system.

The present invention is usable in a touch sensor system configured todetect a touch signal that is based on a touch to a touch panel.Further, the present invention is applicable to an electronic blackboardsystem.

REFERENCE SIGNS LIST

-   1 touch sensor system-   2 sensor panel

3 integrated circuit

4 drive section

5 estimation section

6, 6A analog integrator

7 switch

8 AD converter

9 inner product computing section

10 RAM

11 application processing section

12 mobile telephone

13 display panel

14 display control circuit

15 CPU

16 ROM

17 RAM

18 microphone

19 loud speaker

20 operation key

21 camera

101 touch sensor system

102 touch panel

103 hand placing region processing section (first processing means)

104 plot input processing section (second processing means)

105 driver

106 sense amplifier

107 AD converter

108 decoding section

109 display panel

110 hand placing region setting section (hand placing region settingmeans)

111 automatic setting section (automatic setting means)

112 two-dimensional region

113 hand placing region (partial region)

114 remainder region

115 control circuit

116 a to 116 d region

117 region

118 stylus input region

119 pad menu

120 stylus input trail

The invention claimed is:
 1. A touch sensor system, comprising: acontrol circuit including: a driving section that (a) drives, on a basisof code sequences di (=di1, di2, . . . , diN, where i=1, . . . , M)which are orthogonal to one another and include elements each beingeither +1 or −1 and each of which has a length N, M drive lines inparallel for each of (I) a first capacitance column C1i (i=1, . . . , M)formed between the M drive lines and a first sense line and (II) asecond capacitance column C2i (i=1, . . . , M) formed between the Mdrive lines and a second sense line, so that a voltage +V is applied foran element of +1 in the code sequences and that a voltage −V is appliedfor an element of −1 in the code sequences, and thus (b) outputs sFirst=(s11, s12,. . . , s1N) from the first capacitance column and outputssSecond =(s21, s22, . . . , s2N) from the second capacitance column; andan estimation section that estimates, (a) on a basis of a first innerproduct operation of the outputs sFirst and the code sequences di, afirst capacitance value in the first capacitance column which firstcapacitance value corresponds to a k1-th drive line and (b) on a basisof a second inner product operation of the outputs sSecond and the codesequences di, a second capacitance value in the second capacitancecolumn which second capacitance value corresponds to a k2-th drive line;and a sensor panel corresponding to the drive lines, the sense lines,the first capacitance column, and the second capacitance column, thesensor panel including a two-dimensional region including at least onepartial region and a remainder region being a region other than thepartial region; wherein the control circuit, carries out a first processin accordance with a partial region touch signal corresponding to atouch to the partial region; and carries out a second process inaccordance with a remainder region touch signal corresponding to a touchto the remainder region, the second process being different in kind fromthe first process, the partial region is a palm placing region thatcorresponds to a non-input region where a palm is placed during userinput to the sensor panel, of the palm placing region and the remainderregion, only the palm placing region is arranged to move within thetwo-dimensional region so as to follow movement of the center of mass ofthe partial region touch signal which corresponds to where the palm isplaced during user input to the sensor panel, and the remainder regiontouch signal corresponds to a plot signal generated by a stylus and/or atouch signal generated by a finger.
 2. An electronic device, comprising:the touch sensor system recited in claim 1; and a display panel whicheither is placed on the sensor panel included in the touch sensor systemor contains the sensor panel.
 3. A touch sensor system, comprising: asensor panel including (I) a first capacitance column C1i (i=1, . . . ,M) formed between M drive lines and a first sense line and (II) a secondcapacitance column C2i (i=1, . . . , M) formed between the M drive linesand a second sense line; and an integrated circuit for controlling thesensor panel, the integrated circuit including: a drive section for (a)driving, on a basis of code sequences di (=di1, di2, . . . , diN, wherei=1, . . . , M) which are orthogonal to one another and include elementseach being either +1 or −1 and each of which has a length N, the M drivelines in parallel for each of (I) the first capacitance column C 1 i(i=1, . . . , M) and (II) the second capacitance column C2i (i=1, . . ., M) so that a voltage +V is applied for an element of +1 in the codesequences and that a voltage −V is applied for an element of −1 in thecode sequences, and thus (b) outputting outputs sFirst =(s11, s12, . . ., s1N) from the first capacitance column and outputs sSecond =(s21, s22, . . . , s2N) from the second capacitance column; and an estimationsection for estimating (a) on a basis of a first inner product operationof the outputs sFirst and the code sequences di, a first capacitancevalue in the first capacitance column which first capacitance valuecorresponds to a k1-th drive line and (b) on a basis of a second innerproduct operation of the outputs sSecond and the code sequences di, asecond capacitance value in the second capacitance column which secondcapacitance value corresponds to a k2-th drive line, the sensor panelincluding a two-dimensional region including at least one partial regionand a remainder region being a region other than the partial region,wherein the integrated circuit: carries out a first process inaccordance with a partial region touch signal corresponding to a touchto the partial region; and carries out a second process in accordancewith a remainder region touch signal corresponding to a touch to theremainder region, the second process being different in kind from thefirst process, the partial region is a palm placing region thatcorresponds to a non-input region where a palm is placed during userinput to the sensor panel, of the palm placing region and the remainderregion, only the palm placing region is arranged to move within thetwo-dimensional region so as to follow movement of the center of mass ofthe partial region touch signal which corresponds to where the palm isplaced during user input to the sensor panel, and the remainder regiontouch signal corresponds to a plot signal generated by a stylus and/or atouch signal generated by a finger.
 4. An electronic device, comprising:the touch sensor system recited in claim 3; and a display panel whicheither is placed on the sensor panel included in the touch sensor systemor contains the sensor panel.
 5. A touch sensor system, comprising: acontrol circuit including, a driving section that (a) drives, on a basisof code sequences di (=di1, di2, . . . , diN, where i=1, . . ., M) whichare orthogonal to one another and include elements each being either +1or −1and each of which has a length N, M drive lines in parallel foreach of (I) a first capacitance column Ci1 (i=1, . . . , M) fowledbetween the M drive lines and a first sense line and (II) a secondcapacitance column Ci2 (i=1, . . . , M) formed between the M drive linesand a second sense line, and thus (b) outputting, to an analogintegrator, outputs sFirst =(s11, s12, . . . , s1N) from the firstcapacitance column and outputs sSecond =(s21, s22, . . . , s2N) from thesecond capacitance column; and an estimation section that estimates, (a)on a basis of a first inner product operation of the outputs sFirst andthe code sequences di, a first capacitance value in the firstcapacitance column which first capacitance value corresponds to a k1-thdrive line and (b) on a basis of a second inner product operation of theoutputs sSecond and the code sequences di, a second capacitance value inthe second capacitance column which second capacitance value correspondsto a k2-th drive line, the driving section, for an element of +1 in thecode sequences, driving the drive lines at (i) a first voltage when theanalog integrator is reset and (ii) a second voltage when the outputssFirst and sSecond from the first and second capacitance columns aresampled and, for an element of −1 in the code sequences, driving thedrive lines at (i) the second voltage when the analog integrator isreset and (ii) the first voltage when the outputs sFirst and sSecondfrom the first and second capacitance columns are sampled, the touchsensor system further comprising: a sensor panel corresponding to thedrive lines, the sense lines, the first capacitance column and thesecond capacitance column, the sensor panel including a two-dimensionalregion including at least one partial region and a remainder regionbeing a region other than the partial region; wherein the controlcircuit, carries out a first process, in accordance with a partialregion touch signal corresponding to a touch to the partial region; andcarries out a second process in accordance with a remainder region touchsignal corresponding to a touch to the remainder region, the secondprocess being different in kind from the first process, the partialregion is a palm placing region that corresponds to a non-input regionwhere a palm is placed during user input to the sensor panel, of thepalm placing region and the remainder region, only the palm placingregion is arranged to move within the two-dimensional region so as tofollow movement of the center of mass of the partial region touch signalwhich corresponds to where the palm is placed during user input to thesensor panel, and the remainder region touch signal corresponds to aplot signal generated by a stylus and/or a touch signal generated by afinger.
 6. An electronic device, comprising: the touch sensor systemrecited in claim 5; and a display panel which either is placed on thetouch panel included in the touch sensor system or contains the touchpanel.